SB 



608 ■ 



Principal Insect Enemies 



OF THE 



SUGAR BEET 



IN THE TERRITORIES SERVED BY 

The Great Western Sugar Company 



BY 



ASA C. MAXSON 

In Charge, Experimental Department 








Published by 
AGRICULTURAL DEPARTMENT 
THE GREAT WESTERN SUGAR COMP 
DENVER, COLORADO 

1920 



Principal Insect Enemies 



OF THE 



SUGAR BEET 

1N THE TERRITORIES SERVED BY 

The Great Western Sugar Company 



BY 

ASAC.MAXSON 

In Charge, Experimental Department 






Published by 
AGRICULTURAL DEPARTME^ 
THF GREAT WESTERN SUGAR COMPAN 
THE GRLA DENVERi COLORADO 

1920 



S6 c 

I H3 



PREFACE 

Some damage is done by some pest somewhere every year, causing 
some loss to individual farmers. Fortunately, we have been free so far 
from pests damaging very large areas in any one year, and it is confidently 
hoped that this will always be the case in the territory served by this Com- 
pany. Nevertheless, it seems wise to have on hand all the information 
necessary to enable growers to apply proper measures in case of emergency. 

There are available a number of bulletins and books published by the 
Department of Agriculture, Agricultural Colleges and others, dealing with 
insect pests damaging to sugar beets, but it has been thought of interest 
and value to beet growers to have this information presented in one book 
and with due regard to local conditions. 

While it is hoped that this Bulletin will be of valuable assistance to 
the grower of sugar beets by presenting the best known methods of pre- 
venting injury and controlling insects which damage this crop, it seems 
desirable to impress upon him the fact that there is no magical method, no 
patent medicine, which can be quickly and easily applied. 

Good farming, as taught by local experience, practiced con- 
sistently every year, will produce bigger yields of beets and min- 
imize the damage done by insects or beet diseases. 

For the benefit of those wishing to study the subject more completely, 
scientific names of insects, other invertebrate animals, and plants discussed, 
have been given in the Appendix, pages 138 to 146, together with credit 
for determination. Free use has been made of the literature of beet insects 
and credit given where it has been quoted. 

This Bulletin has been prepared by Mr. A. C. Maxson, Entomologist 
in charge of the Company's Experimental Farm at Longmont, Colorado. 

Credit is due Miss Caroline M. Preston for reproducing the insects 
for the colored plates. 

THE GREAT WESTERN SUGAR COMPANY 



TABLE OF CONTENTS 

Page 

Introduction 1 

Outline of the Bulletin 3 

Key for Determining Insect Injury to Sugar Beets: 

Explanation of Key 4 

The Key 5 

Colored Plates 11 

CHAPTER I 

Insects in General 29 

Structure 29 

Development 29 

The Egg 30 

The Larva 30 

The Pupa 30 

The Adult 30 

The Integument 30 

Classification 31 

Root Feeders 31 

Leaf Feeders 31 

Biting Insects 31 

Sucking Insects 31 

Methods of ; Control 31 

Natural Methods 31 

Crop Rotation 31 

Plowing 32 

Late Planting 32 

Burning 32 

Clean Culture 32 

Artificial Methods — Insecticides 32 

Control of Biting Insects 32 

Control of Sucking Insects — Contact Poisons 33 

Repellents 33 

Sprayers 33 

Traction Sprayer 33 

Care of Sprayers 34 

Knapsack Sprayer 36 

Hand Sprayer 36 

Home-made Sprayer 37 

Paris^Green, Caution Regarding the Handling of 37 

iii 



Table of Contents 

CHAPTER II 

Page 

Root Feeders 38 

A. Biting Root Feeders 38 

1 . Cutworms 38 

a. Western Army Cutworm 41 

b. Pale Western Cutworm 45 

c. Variegated Cutworm 47 

2. White Grubs 48 

3 . Wireworms 52 

B. Sucking Root Feeders 55 

1 . Sugar Beet Root-louse 55 

2. Sugar Beet Nematode 59 

3. Root-knot Nematode or Gallworm 64 

CHAPTER III 

Leaf Feeders 67 

A. Biting Leaf Feeders 67 

1 . Leaf-eating Caterpillars 67 

a. Sugar Beet Webworm 67 

b. True Army Worm 78 

c. Alfalfa Looper 81 

d. Alfalfa Webworm 84 

e. Yellow-bear Caterpillar 86 

f. Zebra Caterpillar 87 

2. Leaf-eating Beetles 88 

a. Larger Sugar Beet Leaf-beetle or Alkali-beetle 89 

b. Western Beet Leaf-beetle 90 

c. Flea-beetles 91 

c-1 . Banded Flea-beetle 92 

c-2. Potato Flea-beetle 93 

c-3. Three-spotted Flea-beetle 93 

d. Spinach Carrion-beetle 94 

e. Blister-beetles 96 

3 . Grasshoppers 98 

a. Two-lined Hopper 100 

b. Differential Hopper 100 

c. Red-legged Locust 100 

4. Field Crickets 109 

5. Leaf-miners 110 

a. Beet or Spinach Leaf-miner 110 

iv 



Table of Contents 

Leaf Feeders — Continued Page 

B. Sucking Leaf Feeders Ill 

1 . Aphids or Plant-lice Ill 

a. Green Peach-aphis 116 

b. Black Beet-seed Louse 117 

2. True Bugs '. . 119 

a. False Chinch Bug 119 

b. Tarnished Plant-bug 122 

3 . Leaf-hoppers 1 23 

a. Sugar Beet Leaf-hopper 123 

b. Clover Leaf-hopper 126 

c. Eutettix strobi Fitch 128 

CHAPTER IV 

Beneficial Insects 129 

A. Predacious Insects 130 

1 . Ground Beetles 130 

a. Fiery Hunter 130 

b. Bombardier-beetles 130 

2. Tiger-beetles 131 

3. Lady-beetles or Lady-bugs 132 

4. True Bugs 132 

a. Assassin-bugs 133 

b. Ambush-bugs 133 

c. Stink-bugs 133 

5. Lace-winged Flies 133 

6. Wasps 134 

a. Digger-wasps 134 

a-1. Family Scoliidae 134 

a-2. Spider-wasps 134 

a-3. Thread-waisted wasps 134 

b. Solitary Wasps 135 

B. Parasitic Insects 135 

1 . Ichneumon-flies 136 

2. Braconids 136 

3. Chalcis-flies 137 

Appendix 138 

Bibliography 147 

Index 149 



LIST OF TEXT FIGURES 

Page 

Fig. 1 A good type of traction sprayer for field use. (Original) 33 

Fig. 2 Knapsack sprayer. (Original) 36 

Fig. 3 Hand sprayer. (Original) 36 

Fig. 3-a A Home-made sprayer - 37 

Fig. 4 Scales from wing of moth of western army cutworm, highly 

magnified. (Original) ' 42 

Fig. 5 Adult snapping-beetle, Alaus ocutatus. The larvae of this 

beetle feed upon decaying wood. (Original) 52 

Fig. 6 A sugar beet infested with sugar beet namatodes. The white 
bodies of the female nematodes can be seen clinging to the 

rootlets. (Original) 60 

Fig. 7 A sugar beet affected with curly-top, showing the character- 
istic dense mass of rootlets. (After C. O. Townsend, 
Farmers' Bulletin No. 122, U. S. Department of Agri- 
culture) 60 

Fig. 8 Small sugar beets infested with the root-knot nematode. The 
bead-like swellings on the small roots and the enlarge- 
ments of the main root are caused by the nematodes. 

(Original) 64 

Fig. 9 Sugar beet badly damaged by webworms 69 

Fig. 10 Sugar beets badly damaged by webworms 70 

Fig. 1 1 Field of sugar beets showing work of the sugar beet webworm. 

(Original) '. 71 

Fig. 12 Result of spraying— left, unsprayed; right, sprayed 73 

Fig. 13 A portion of the compound eye of a tiger-beetle, highly mag- 
nified. (Original) 76 

Fig. 14 Cross section through burrow of the solitary wasp. 

(Original) .'..'.'■ 78 

Fig. 15 Hopper dozer. (After Charles R. Jones, Bulletin No. 233, 

Colorado Agricultural Experiment Station) 102 

Fig. 16 Exposed grass roots, showing grasshopper eggs and larvae of 

the ground beetle, Amara obesa. (Original) 106 

Fig. 17 Hair worm escaping from a parasitized ground beetle. 

(Original) 107 

Fig. 18 The hair worm shown in Figure 17, after it had escaped from 

the beetle. (Original) 108 

Fig. 19 Grasshoppers killed by the fungous disease, Empusa grylli. 

(Original) 109 



VI 



List of Text Figures 

Page 

Fig. 20 An exposed colony of plant-lice on a common roadside weed. 

(Original) 112 

Fig. 21 Leaves of white ash curled by a plant-louse. (Original) 112 

Fig. 22 Gall of sugar beet root-louse on leaves of narrow-leaf Cot- 
tonwood. (Original) 113 

Fig. 23 A common wingless aphid; honey tubes at "A". (Original) . . 1 13 

Fig. 24 A branch of Euonymus species, showing star-shaped fruit. 

(Original) 118 

Fig. 25 Sugar beet showing characteristic curling of leaves caused by 
curly-top. (After Harry B. Shaw, Bulletin No. 181, U. 
S. Bureau of Plant Industry) 124 

Fig. 26 Cross section of sugar beet, showing darkening of rings caused 
by curly-top. (After C. O. Townsend, Bulletin No. 122, 
U. S. Bureau of Plant Industry) 125 

Fig. 27 Entrance to burrow of tiger-beetle larva. There is never any 

loose soil at the entrance to these burrows. (Original) . . 131 

Fig. 28 Same burrow as shown in Figure 27, with head of larva resting 
on level with the surface, ready to seize a victim. (Orig- 
inal) ". 131 

Fig. 29 Nest of a mud-dauber, taken from rafter of an out-building. 

(Original) 135 

Fig. 30 A cabbage-worm killed by the larvae of a Braconid, the 
cocoons of which are fastened to the window screen near 
it. (Original) 136 



INTRODUCTION 

The impression may be gained that the sugar beet is especially 
liable to insect injury because of the bringing together of so much on the 
subject. However, this is not the case. A study of crop insects shows 
that most crops have an equal number of insect enemies and many have 
more. It should be emphasized that everything known to good farming 
practice in beet culture, such as rotation of crops, manuring, clean culture, 
and timeliness of plowing and irrigating, tends to minimize damage by 
insects. 

OUTLINE OF THE BULLETIN 

By knowing in advance the structural plan of the Bulletin, reference 
can more readily be made to any desired part. Hence an outline is 
given on page 3. Furthermore, the use of this Outline in conjunction 
with the "Key for Determining Insect Injury to Sugar Beets" (pages 5 
to 8) may aid in identifying insects. For example, if it is known that 
damage is being done to the leaves of the beets and that the insects caus- 
ing it are "Biting" insects, and if it is known that they are not beetles or 
grasshoppers, then it can, for practical purposes, be concluded that the 
damage is being caused by either leaf-miners or caterpillars, and by 
referring to the text cited, a conclusion can in most cases be drawn regard- 
ing the particular insect causing the damage. If one of the suspected 
insects has been caught, the Colored Plates (See pages 11 to 27) 
will greatly facilitate its identification. 

KEY FOR DETERMINING INSECT INJURY TO SUGAR BEETS 

In order to facilitate the use of this Bulletin for reference purposes, 
a short "Key for Determining Insect Injury to Sugar Beets" has been 
constructed. (See pages 5 to 8.) If the nature of the insect damage is 
known, reference to this "Key" should enable one to determine the gen- 
eral class of insect doing the damage, if not the particular insect. By 
looking up the descriptive pages cited in the "Key", and by checking 
the Colored Plates against the suspected insect, if one has been 
caught, a reasonably strong case can probably be established. 

COLORED PLATES 

It took the artist three seasons to complete the drawings from which 
the Colored Plates were made. Every insect was drawn directly from 
a live specimen, and the form and colors are true to life. 

Some of these colored pictures were enlarged. In nearly all such 
cases a small black and white outline at the left or right of the colored 
picture shows the natural size of the specimen. The exceptions are 
clearly noted on the title pages. 

Pictures as well prepared as these carry descriptions much more 
quickly and accurately than words, especially to persons not trained to 
think in entomological terms. 

1 



Introduction 

The main purpose of all this care in preparing these Colored Plates 
is to enable the reader to identify, in the easiest and most positive manner 
possible, any specimens he may have procured. 

The title page opposite each plate gives the name of each specimen 
and indicates the pages of the Bulletin on which it is discussed. 

Additional help in locating the pages on which any individual insect 
is discussed may be had from the Outline of the Bulletin (page 3), the 
"Key for Determining Insect Injury to Sugar Beets" (pages 5 to 8), 
the Appendix (pages 138 to 146), and Index (pages 149 to 157). 

THE APPENDIX 

The Appendix (pages 138 to 146) contains an alphabetical list of the 
popular names of insects and plants discussed, together with their scien- 
tific names, credit for their determination, and illustration and page 
references. The Appendix is mainly for the benefit of those wishing jx> 
study the subject more fully than has been done in this Bulletin. 

THE INDEX 

The Index will be found at the back of the book, on pages 149 
to 157. 

THREE METHODS FOR LOCATING DESIRED TEXT 

1. If you know the name of the insect, use the Index (pages 149 
to 157) or the Appendix (pages 138 to 146) to find the pages of the 
Bulletin on which it is discussed. 

2. If you know the nature of the damage, but not the name of the 
insect doing it, use the "Key for Determining Insect Injury to Sugar 
Beets" (pages 5 to 8) or the Outline (page 3). 

3. If you have one of the suspected insects, but do not know its 
name, use the Colored Plates (pages 1 1 to 27) . 

Use both Methods 2 and 3 when possible, to make identification 
more positive. 

In case of doubt as to the identity of an insect or other specimen, 
or as to the nature of an injury, competent advice can always be obtained 
by consulting the authorities of the Agricultural College, the County 
Agents, or The Great Western Sugar Company's fieldmen. 

REFERENCE FIGURES 

The small elevated figures found occasionally throughout the text 
after the mention of some insect, refer to the corresponding marginal 
figure in the Appendix. The purpose of the reference is to connect the 
particular species to its scientific name. 

BIBLIOGRAPHY 

The Bibliography (pages 147 and 148) contains a list of publications 
on related subjects. Some of these have been drawn upon in the com- 
pilation of this Bulletin, and credit given in the text. 



Introduction 



OUTLINE OF THE BULLETIN 



Introduction 

Outline of the Bulletin 

Key for Determining Insect Injuring Sugar Beets 

Colored Plates 



Chapter I 



Insects in General. 



(a) Structure 

(b) Development 

(c) Classification 

(d) Methods of Control 



Chapter II 



Root Feeders (a) Biting . 



(b) Sucking. 



(1) Cutworms 

(2) White Grubs 

(3) Wireworms 

(1) Sugai Beet Root-louse 

(2) Sugar Beet Nematode 

(3) Root-knot Nematode or 

Gallworm 



Chapter III 



Leaf Feeders (a) Biting. 



(b) Sucking. 



.(1) 
(2) 
(3) 
(4) 
(5) 
(1) 
(2) 
(3) 



Caterpillars 
Beetles 
Grasshoppers 
Field Crickets 
Leaf-miners 
Aphids or Plant-lice 
True Bugs 
Leaf-hoppers 



Chapter IV 



Beneficial Insects. ... (a) Predacious. 



(b) Parasitic. 



(1) Beetles 

(2) True Bugs 

(3) Lace-winged Flies 

(4) Wasps 

( 1 ) I chneumon-fl ies 

(2) Braconids 

(3) Chalcis-flies 



Appendix 

Bibliography 

Index 



Introduction 



EXPLANATION OF KEY FOR DETERMINING INSECT 
INJURY TO SUGAR BEETS 

The method of using the Key (pages 5 to 8) is illustrated below 
by imagining a case of injury and following it through the Key until 
we come to the point where we get a clue to the insect causing the damage. 

Example: In going through the field while the thinners are at work, 
we notice a beet here and there which is wilted and cut off just below 
the surface of the ground. Take your Key and begin at "A." This 
says that the leaves of the plant are wilted while those of the surround- 
ing plants remain normal. This is true of the plants we found, so we read 
what comes under "1." As our beet is cut off below the surface of the 
ground "1" fits our case, so we continue to "a" and read: "Plants small. 
Damage occurring before or shortly after blocking and thinning". As the 
thinners are at work in our field this again fits our case, so we pass on 
to the single star (*). Here we read: "Plants cut off at or just below 
the surface of the ground," etc. This is our case exactly, and at the end 
we read: "Look for Cutworms." Thus the Key indicates that cut- 
worms are at work on our beets and refers us to pages 38 to 48 of the 
Bulletin, where this insect is discussed. 

Let us suppose that when we read the paragraph under the single star 
(*) we found that this did not describe our beet. We would then pass 
on to the double star (**), and if the beet we have has been injured by 
any of the insects discussed in this Bulletin this paragraph should describe 
the way it is injured. 

If the injury was not indicated by a wilting of the leaves we pass 
from the capital "A" to capital " B", on page 6, and if this does not fit 
our case we pass on through the capital letters until we do find the de- 
scription. When we find it we pass through the other steps which are 
indicated by figures, small letters, etc., until we come to the place where 
the insect causing the injury is named. 

While this Key may not fit all cases exactly, yet it should enable 
one to determine quite closely what insect is causing the injury noticed. 
Then if the discussion of this insect and the nature of its injury are read 
and the insect, if one is secured, is compared with the pictures in the 
Colored Plates, there should be little difficulty encountered in identifying 
the culprit. 

In case of doubt competent advice can always be obtained by con- 
sulting the authorities of the agricultural colleges, county agents or the 
sugar company's fieldmen. 



Introduction 



KEY FOR DETERMINING INSECT INJURY TO SUGAR BEETS 

A. Leaves of plant wilted while those of surrounding plants re- 
main normal. 

1. Plants cut off above the surface of the ground, at varying depths 

below, or with portions of the root surface eaten away, leaving 
shallow depressions or deep pits with darkened walls. 

a. Plants small. Damage occurring before or shortly after 

blocking and thinning. 

* Plants cut off at or just below the surface of the ground. 

Damage most apt to occur where beets follow alfalfa 
or grain, timothy or abandoned crops, and on fields ad- 
jacent to alfalfa. 

Look for Cutworms (pages 38-48). 

** Plants cut off an inch or so below the surface of the 
ground. Tip of root as pulled from the ground dark, 
almost black. Damage most apt to occur where beets 
follow alfalfa, sod, pasture or meadow. 

Look for : White Grubs (pages 48-52) ; 
Wireworms (pages 52-54). 

b. Beets larger. Damage occurring from time roots attain the 

size of one's finger until harvest. 

* Plants always cut off above surface of ground or with 

deep cavities pecked into the crowns. Damage most 
apt to occur near standing alfalfa or waste land over- 
grown with weeds or other tall growth. 

Damage caused by Pheasants. 

** Plants never cut off above the surface of the ground. 

Portions of root surface eaten away, leaving shallow 
depressions with rough darkened surface. Root 
often entirely eaten off several inches below the 
surface of the ground. Damage usually occurring 
where beets follow sod, pasture or meadow, or on 
river bottom land. 

Look for White Grubs (pages 48-52). 

00 Portions of root surface eaten away, leaving small, 
deep, dark-walled pits. Roots of large beets never 
entirely eaten off. Damage most apt to occur 
where beets follow alfalfa, sod, pasture or meadow. 

Look for Wireworms (pages 52-54). 

2. Plants not cut off. Portions of root surface not eaten away. 

Leaves often dull, dark green, as though plants were suffering 
from lack of moisture; or leaves yellowish green. 



Introduction 

a. Only young heart leaves wilted. Wilting usually most appar- 

ent at tip of leaves. Later these tips become dry and brown. 

Look for Tarnished Plant-bugs (pages 
122-123). 

b. Entire plant more or less wilted. 

* Root either covered with whitish substance or with abnor- 
mal development of fine roots or wart-like swellings. 

Root more or less covered with a white mould-like 
substance. Many whitish-yellow lice mixed with 
this substance. Lice present in nearly every 
field regardless of previous crop. Damage more 
apt to be severe in dry years than wet. 

Sugar Beet Root-lice (pages 55-59). 

00 Root with abnormal development of fine rootlets. 
Many small pearly-white bodies clinging to these 
rootlets. (See Figure 9, Plate III, Page 15 and 
Figure 6, Page 60). In late fall many of these 
bodies become rich brown in color. Injury most 
apt to occur on old beet ground. 

Sugar Beet Nematode (pages 59-64). 

000 Roots with wart-like swellings. Rootlets with 
small, almost round swellings resembling beads on 
a string. (See Figure 8, Page 64). Injury most 
apt to occur on old beet ground. 

Root-knot Nematode or Gallworm 
(pages 64-66). 

** Root normal. Not as above. 

Damage usually most severe in fields near poor 
stands of alfalfa overrun by shepherd's-purse, 
fanweed and other weeds of the mustard family. 
Fields adjacent to waste land overgrown with 
these weeds very apt to be damaged, also, as weeds 
begin to ripen. 

Look for False Chinch Bugs (pages 1 19- 
121). 

B. Leaves dull green, light yellow, or blotched with whitish green 
or purple. 

1. Leaves dull green, as though plants were suffering from lack of 
moisture. In severe cases leaves become light yellowish green. 
Plants making poor growth. 

Look for : Sugar Beet Root-lice (pages 
55-59); 
Nematodes (pages 59-66). 



Introduction 

2. Leaves blotched with whitish green. Not abnormally curled. 

Look for : Plant-lice (pages 111-116), 

Leaf-hoppers (pages 123-128). 

3. Leaves blotched with purple (Figure 1, Plate VIII, Page 25). 

Look for Leaf-hoppers (pages 123-128). 

C. Leaves with portions of blade or stem eaten away. Sometimes 
crowns of beets eaten also. 

1. Leaves eaten full of small holes (Figure 1, Plate IV, Page 17). 

Injury most apt to occur during spring and early summer. 

Look for Flea-beetles (pages 91-93). 

2. Leaves more or less completely eaten, or portions eaten from mar- 

gins (Figure 11, Plate III, Page 15V 

a. Leaves often more or less covered with a fine whitish web. 

Damage caused by worms about one inch long when fully 
grown. Worms -very active, throwing themselves from the 
plant when disturbed. Often hanging from leaf by a single 
thread of web, especially when young. 

* Worm dark green, striped, several dark circular spots on 
each segment of the body (Figure 6, Plate V, Page 
19). Web when present usually on blade of leaf near 
its base. Heart leaves usually eaten last. Excrement 
of worms scattered over leaves in form of small dark 
pellets. 

Sugar Beet Webworms (pages 67-78). 

** Worm lighter than webworm. A pink or flesh-colored 
stripe on each side (Figure 1, Plate VI, Page 21). 
Web often among heart leaves. A long tube leading 
from web to clods on the surface of the ground. Worm 
usually concealed at end of this tube when not feeding. 

Alfalfa Webworms (pages 84-85). 

b. Leaves not webbed. 

* Damage occurring during spring and early summer, while 
beets are still small. 

° Damage usually most severe on wet alkali land or 
near such land. 

Look for Alkali-beetles (pages 89-90). 

co Damage not associated with alkali land. Usually 
most severe near alfalfa, ditch banks, fence rows 
or waste land. Edges of leaves eaten. In severe 
cases entire plant destroyed. 

Look for Spinach Carrion-beetles (pages 
94-95). 



Introduction 
** Damage usually occurring during midsummer or later. 

° Damage most severe on wet alkali land or near such 
land. Tender portion of leaf eaten, only a net- 
work of veins remaining, which soon become dry 
and brown. 

Look for Alkali-beetles (pages 89-90). 

° Damage usually most severe at borders of fieldjnear 
wild land, waste land, ditch banks and fence rows 
where grasshoppers are numerous, or near alflafa 
or waste land overrun with sweet clover, or near 
grain fields. 

Look for: Grasshoppers (pages 98-109); 

Alfalfa Loopers (pages 81- 
84); 

Western Army Cutworms 
(pages 41-45). 

000 Damage usually slight, only a beet leaf here and 
there being eaten. Not confined to border, but 
occurring throughout entire field. 

Look for : Yellow-bear Caterpillars (pages 
86-87) ; 

Zebra Caterpillars (pages 87-88) ; 
Variegated Cutworms (pages 47-48). 

D. Leaves very much curled and distorted. Veins much enlarged, 
often bearing cone-shaped points (Figure 5, Plate VIII, Page 
25). Root small and stunted. Rootlets abnormally de- 
veloped (Figure 7, Page 60). Crown often covered with a 
sticky syrup-like substance. Curly-top (pages 124-125). 

Look for Sugar Beet Leaf-hoppers (Pages 
123-126). 



COLORED PLATES 



PLATE I Pam> 

Page 

Fig. 1 Western Army Cutworm, Chorizagrotis auxiliaris Grt 41 

2 Western Army Cutworm, pupa 41 , 46 

3 Western Army Cutworm, adult moth 41, 42, 88 

4 Western Army Cutworm, wing of dark individual 41, 42 

5 An Ichneumon-fly parasite of the Western Army Cutworm, 

Amblyteles longula Cress. (Enlarged) 43, 136 

6 A Braconid parasite of the Western Army Cutworm — Mic- 

rogaster species (Enlarged) 43, 136, 137 

7 Cocoon of Microgaster species (Enlarged) 44, 136, 137 

8 Chalcis-fly parasite of cutworms, Berecyntus bakeri bakeri 

Howard (Enlarged) 44, 1 37 

9 Pale Western Cutworm, Porosagrotis orthogonia Morr 45 

10 Pale Western Cutworm, adult moth 45, 46 

1 1 Eggs of Pale Western Cutworm (Enlarged) 42, 45, 46 

12 Egg of Pale Western Cutworm (Natural size) 42, 45, 46 

1 3 Wireworm 52, 53 

14 Last segment of Wireworm (Enlarged) 52, 53 

1 5 Wireworm pupa 52, 54 

16 Adult Wireworm, Hemicrepidius memnonius Herbst .... 52, 53, 54 

1 7 Adult Wireworm (Enlarged) 52, 54 

18 Larva of adult Wireworm shown in Figure 17 52, 53 

19 White Grub '. 48, 51 

20 A small white grub which feeds upon decayed vegetable 

matter 48, 5 1 

2 1 True Army Worm 78, 80 

22 True Army Worm 78, 80 

23 Adult White Grub, Ligyrus gibbosus De G 48, 5 1 

24 Pupa of True Army Worm 78, 80 

25 Adult True Army Worm 78, 80 

Note: In case of enlargement, a natural size black and 
white outline drawing is shown beside the colored picture. Ex- 
ceptions to this plan on Plate I are Figures 7 and 14. 



10 



PLATE. I 




/i 9 . 23 



fif 24- 



r,g.25 



II 



PLATE II 

Sugar Beet Root-louse, Pemphigus betae Doane Paee 

Fig. 1 Newly hatched louse feeding on Cottonwood leaf (See "A") . 55, 58 

2 Newly hatched louse (Enlarged) 55, 57 

3 Upper side of leaf after gall becomes closed 55, 58 

4 Side view of young gall 55, 58 

5 Fully developed gall 55, 58 

6 Full grown stem-mother (Enlarged) 55, 58 

7 Full grown second generation louse (Spring migrant) 

(Enlarged) 55, 58 

8 Antenna of Figure 7 (Enlarged) 55, 58 

9 Wingless form of sugar beet root-louse found on beets dur- 

ing summer (Enlarged) 55, 58 

10 A lady-beetle which feeds upon sugar beet root-lice (En- 

larged) 59, 115, 132 

1 1 Antenna of wingless louse (Enlarged) 55, 58 

12 Antenna of wingless louse (Enlarged) 55, 58 

13 Antenna of true male sugar beet root-louse, Figure 16 (En- 

larged) 55,57 

14 A true bug, Authocoris melanocerus, which feeds on lice in 

gall (Enlarged) 59, 132 

15 Larva of lady-beetle (Figure 10), which also feeds on lice 

while on beets (Enlarged) 59, 115, 132 

16 True male sugar beet root-louse (Much enlarged. Note 

minute representation of actual size at left of colored 
picture) 55, 57 

17 Solitary egg laid by female sugar beet root-louse (Enlarged). 55, 57 

18 True female sugar beet root-louse (Much enlarged. Note 

minute representation of actual size at left of colored 
picture) 55,57 

Note: Incase of enlargement, a natural size black and 
white outline drawing is shown beside the colored picture. Ex- 
ceptions to this plan on Plate II are Figures 2, 8, 11, 12, 13 

and 17. 



12 




% F/g/S 



Fig. /6 F>9 17 



13 



PLATE III 

Page 

Fig. 1 Beet leaf showing mines made by Beet Leaf-miner (Fig. 3), 

and eggs (Fig. 3-A) 1 10, 1 

2 Eggs of Beet Leaf-miner (Enlarged) 1 10, 1 

3 Beet Leaf-miner (Enlarged) 1 10, 1 

4 Puparium of Beet Leaf-miner (Enlarged) 110, 1 

5 Adult Beet Leaf-miner, Pegomyia vicina Lintn. (Enlarged) 1 10, 1 

6 Black Beet-seed Louse, Aphis euonymi Fabr. (Enlarged) 1 17, 1 

7 Winged form of Black Beet-seed Louse (Enlarged) 117, 1 

8 Sugar Beet Nematode, Heterodera schachtii Schmidt (Adult 

female, much enlarged. The nematode is almost 
microscopic in size) 59, 64 

9 Young beet showing female nematodes on rootlets (Slightly 

enlarged) 59, 61 

10 Adult male nematode (Much enlarged) 59, 64 

1 1 Zebra Caterpillar, Mamestra picta Harr, feeding on beet leaf . 87, 88 

Note: In case of enlargement, a natural size black and 
white outline drawing is shown beside the colored picture. Ex- 
ceptions to this plan on Plate III are Figures 2, 8, 9 and 10. 



14 



PLAT EEL 




15 



PLATE IV Page 

Fig. 1 Work of flea-beetles on a beet leaf 89, 91 

2 Adult Banded Flea-beetle, Systerxa taeniata Say (Enlarged) 92 

3 A flesh-fly parasite of grasshoppers, Sarcophage variacauda 

Coq. (Enlarged) 105 

4 Maggot of Figure 3 (Enlarged) 1 05 

5 Adult Potato Flea-beetle, Epitrix cucumeris Harr. (En- 

larged) 93 

6 Adult Three-spotted Flea-beetle, Disonycha triangularis 

Say (Enlarged) 93 

7 An immature female Field Cricket 109, 1 10 

8 Grasshopper egg-pod 104 

9 Young Two-lined Hopper, Melanoplus bivittatus Say (En- 

larged) 100, 105 

10 Adult female Two-lined Hopper 100, 104 

1 1 Outline drawing of tip of female's abdomen, Two-lined 

Hopper, showing ovipositor 1 00, 1 04 

12 Adult male Differential Hopper, Melanoplus differentialis 

Thos., yellow phase 100 

1 3 Adult male Differential Hopper, black phase 1 00 

14 Adult Red-legged Locust, Melanoplus femur-rubrum De G. 100 

1 5 Outline drawing of last segment of male's abdomen, adult 

Red-legged Locust 1 00 

16 Hair Worm. A parasite of grasshoppers and other insects 

— somewhat enlarged. See also Figures 17 and 18, 
Pages 107 and 108 107, 108 

Note: In case of enlargements, natural size outline 
drawings are shown beside the colored pictures. Excep- 
tions on Plate IV are Figures 9 and 16. 



16 



PLATE JI 




CMPRESTON 



Fig -76 



17 



PLATE V Page 

Fig. 1 A half grown grasshopper with Locust Mites attached 105, 106, 107 

2 Young mite (Enlarged) 1 06, 1 07 

3 Beet leaf with young Sugar Beet Webworm at "A" 67, 75 

4 Young Sugar Beet Webworm (Enlarged) 67, 75 

5 Portion of beet leaf with Sugar Beet Webworm moth eggs 

(Slightly enlarged) 67, 74 

6 Full grown Sugar Beet Webworm (Enlarged) 67, 71, 75 

7 Sugar Beet Webworm parasite, Cremnops vulgaris 77, 136 

8 Sugar Beet Webworm cocoon 67, 75 

9 Pupa of Sugar Beet Webworm 67, 75 

10 Last segment of Sugar Beet Webworm pupa (Enlarged) . .67, 75 

1 1 Adult Sugar Beet Webworm moth, Loxostege sticticalis 

Linn 67, 68, 75, 85 

12 Puparium of figure 13 (Enlarged) 77 

13 A two-winged Tachina-fly parasite (Meteorus loxostegei 

Vier.) of the Sugar Beet Webworm (Enlarged) 77 

1 4 A Braconid reared from a Sugar Beet Webworm (Enlarged) 

77, 136, 137 

1 5 Yellow-bear Caterpillar 86, 87 

16 Adult Yellow-bear Caterpillar, Diacrisia virginica Fab 86, 87 

17 Adult female Locust-mite (Trombedium iocustarum Riley) 

and eggs (Enlarged) 106, 107 

18 Adult male Locust-mite (Enlarged) 106, 107 

Note: In case of enlargement, a natural size black and 
white outline drawing is shown beside the colored picture. Ex- 
ceptions on Plate V are Figures 2, 3, 4 and 10. 



18 




F7f. /S 



19 



Fig. 1 
2 
3 
4 
5 
6 
7 



9 

10 

11 

12 
13 

14 

15 

16 

17 



PLATE VI D 

Page 

Alfalfa Webworm (Enlarged) 83, 84 

Pupa of Alfalfa Webworm 84, 85 

Last Segment of Alfalfa Webworm pupa (Enlarged) 84, 85 

Adult Alfalfa Webworm, Loxostege commixtalis Walker 75, 84, 85 

Alfalfa Looper 81 , 83 

Cocoon of Alfalfa Looper 81 , 83 

Pupa of Alfalfa Looper 81 , 83 

Adult Alfalfa Looper, Autographa gramma californica 

Speyer 81,83 

Itoplectis atrocoxalis Cress, male. An Ichneumon-fly 

parasite of the Alfalfa Looper 83, 136 

Itoplectis atrocoxalis Cress, female. An Ichneumon-fly 

parasite of the Alfalfa Looper 83, 136 

An undetermined Tachina-fly parasite of the Alfalfa Web- 
worm (Enlarged) 85 

A Robber-fly 78 

Syrphus-fly, Syrphus paulxillus Will. (Enlarged) Its larvae 

feed on Beet Root-lice 59, 1 16 

A two-winged fly (Chloropisca glabra Meign.) whose larvae 

are found among Beet Root-lice (Enlarged) 59 

A Solitary-wasp (Odynerus annulatus Say), which places 

webworms in its nest as food for its young 77, 135 

A full grown larva of the Digger-wasp (Fig. 18), surrounded 

by skin of a cutworm 45, 134 

Cutworm with egg of the Digger-wasp (Fig. 18) attached 

near head 45, 1 34 

A Digger-wasp {Sphex luctuosa Snw.) carrying a cutworm 

into its burrow 44, 1 54 

Note: In case of enlargement, a natural size black 
and white outline drawing is shown beside the colored 
picture. Exception on Plate VI is Figure 3. 



20 



PLATE YL 





9 *<* 

/ V 

Fig/S 




Fig. 13 






Fy/7 



Fif/6 




Fig /a 



21 



PLATE VII page 

Fig. 1 Larva of Alkali-beetle (Enlarged) 89, 90 

2 Pupa of Alkali-beetle (Enlarged) 89, 90 

3 Alkali-beetle egg (Enlarged) 89, 90 

4 Alkali-beetle eggs about natural size 89, 90 

5 Adult Alkali-beetle, Monoxia puncticolis Say (Enlarged) . .89, 90 

6 Adult Western Beet Leaf-beetle, Monoxia consputa Lee. 

(Enlarged) 90 

7 Variegated Cutworm 47, 48 

8 Black Blister-beetle, Epicauta pennsyhanica De G. (En- 

larged) 96, 98 

9 Ash-gray Blister-beetle, Macrobasis unicolor Kby. (En- 

larged) 96, 98 

10 Spinach Carrion-beetle, Silpha bituberosa Lee. (Enlarged) . .94, 95 

1 1 Spinach Carrion-beetle larva (Enlarged) 94, 95 

12 Winter larva of a Blister-beetle (Enlarged) 96, 97 

13 The final larval stage of a Blister-beetle (Enlarged) 96, 98 

14 Pupa of the Lady-beetle, Figure 10, Plate II, Page 21 (En- 

larged) 59, 132 

1 5 Adult Variegated Cutworm, Peridroma margaritosa Haw. . .47, 48 

Note: In case of enlargement, a natural size black and 
white outline drawing is shown beside the colored picture. 



22 



pla te m 




Fig/4 



Fy./S 



23 



PLATE VIII Page 

Fig. 1 Sugar beet leaf discolored by feeding of insects shown in 

Figures 3 and 4 128 

2 Eggs of Green Peach-aphis, Myzus persicae Sulz. (En- 

larged) 116, 117 

3 . Nymph of Figure 4 (Enlarged) 128 

4 Adult Leaf-hopper, Eutettix strobi Fitch (Enlarged) 128 

5 Sugar beet leaf affected by Curly-top 123, 124 

6 Nymph of Figure 7 (Enlarged) 123, 126 

7 Sugar beet Leaf -hopper {Eutettix tenella Baker), which 

carries the disease known as Curly-top (Enlarged) .. 123, 126 

8 Clover Leaf- hopper, Agallla sanguinolenta Pro v. (En- 

larged) . . . .'. 126, 127 

9 Wingless Green Peach-aphis (Enlarged) 116 

10 Winged Green Peach-aphis (Enlarged) 116 

1 1 Nymph of False Chinch Bug (Enlarged) 1 19, 121 

12 Adult False Chinch Bug, Nysius ericae Schill. (Enlarged) .119, 121 

Note: In case of enlargement, a natural size black and 
white outline drawing is shown beside the colored picture. The 
only exception to this on Plate VIII is Figure 2. 



24 



PLATE JUL 




25 



PLATE IX 

Beneficial Insects Page 

Fig. 1 Larva of Fiery Hunter, shown in Figure 2 130 

2 Fiery Hunter, Calosoma calldum Fab 54, 130 

3 A common Ground Beetle 130 

4 A cutworm killed by Chalcis-fly parasites 44, 137 

5 Larva of Tiger-beetle 131 

6 Adult Tiger-beetle, Cicindeta vulgaris Say 131, 132 

7 Adult Tiger-beetle, Cicindela purpurea Oliv 131, 132 

8 Eggs of bug shown in Figures 12 and 13 133 

9 An egg shown in Figure 8, much enlarged 133 

10 A half grown nymph of the bug shown in Figure 12 133 

1 1 A newly hatched nymph of the bug shown in Figure 12 (En- 

larged) 133 

12 A predacious bug, Perilius claudus, yellow phase 133 

13 A predacious bug, Perilius claudus, red phase 133 

14 Eggs of Lady-beetle shown in Figure 15 132 

15 Adult Lady-beetle, Hippodamia convergens Guer (En- 

larged) 115, 132 

16 Eggs of Lace-winged Fly, shown in Figure 19 133 

17 Cocoon made by larva (Figure 18) of Lace-winged Fly, 

shown in Figure 19 133, 134 

18 Larva of Lace-winged Fly, shown in Figure 19. Often 

called "Aphis-lion" (Enlarged) 1 16, 133, 134 

19 Adult Lace-winged Fly. Commonly called "Golden-eye" 

(Enlarged) 1 16, 133 

20 Larva of Ground Beetle, Figure 22 (Enlarged). It feeds 

on grasshopper eggs 106, 130 

21 Pupa of Ground Beetle, shown in Figure 22 (Enlarged) . 106, 130 

22 Adult Ground Beetle, Amara obesa Say (Enlarged) 106, 130 

23 Larva of Lady-beetle, Figure 1 5 (Enlarged) 115,132 

24 Pupa of Lady-beetle, Figure 15 (Enlarged) 132 

Note: In case of enlargement, a natural size black and 
white outline drawing is shown beside the colored picture. Ex- 
ceptions on Plate IX are Figures 9, 11, and 22. 



26 



PLATE H 




/7 9 Z4 

cm pRrsroN 



27 



CHAPTER I 



INSECTS IN GENERAL 

Knowledge of the structure, development, classification and methods 
of control of insects in general will enable the reader to understand better 
.the text dealing with any individual insect. The purpose of the brief 
discussion in this chapter is to give that preliminary setting. 

STRUCTURE 

All adult insects have the head, thorax (chest) and abdomen more 
or less distinctly separated. Attached to the front of the head are two 
antennae, or feelers, as they are popularly called. The mouth parts are 
formed for biting or sucking. Those of biting insects, such as grasshop- 
pers, flea-beetles and alkali-beetles, consist of hard, sharp-edged jaws. 
Sucking insects, such as the false chinch bug, plant-lice and others, have 
the mouth parts prolonged into a long, straight beak which is often jointed. 
In the case of moths and butterflies the larvae have biting mouth parts 
while those of the adults are in the form of a slender proboscis, which is 
carried coiled beneath the head. In the adult stage there are always 
three pairs of legs attached to the thorax. These three pairs of legs are 
present in the immature stages of beetles, the true bugs, moths and but- 
terflies, while the young of the two-winged flies, bees, wasps and others 
are legless. Aside from the true legs, which are located near the head, 
caterpillars have from two to twelve fleshy leglike organs on the ab- 
domen. These are called prolegs or props. These prolegs are furnished 
with both hooks and suction pads. Most adult insects have one or two 
pairs of wings, which are also attached to the chest. 

Insects breathe through small openings or spiracles in the abdomen. 
From these openings the air is carried through tubes called tracheae, lead- 
ing to the various parts of the body. 

Spiders, ticks and mites are not insects, but belong to a group of 
invertebrate animals which have the head, thorax and abdomen closely 
united and possess four pairs of legs in the adult stage; however, in the 
immature stages some have but three pairs. 

DEVELOPMENT 

In the course of their development most insects undergo remarkable 
changes in form. These changes constitute what is known as insect 
metamorphosis. 

One order of insects develops without change in form or without 
metamorphosis. The young when hatched from the egg have the same 
form as the adult. A common representative of this group is often seen 
floating in dense masses on water. Another is sometimes seen hopping 
about on the snow during warm days in early spring in northern latitudes. 

The insects belonging to another class undergo considerable change 
in form during their development, but the young resemble the adults 

• 29 



Insects in General 

quite closely; therefore the metamorphosis is said to be incomplete. 
Grasshoppers, plant-lice and the true bugs are common examples of this 
class. The young of these insects are called nymphs. 

The early forms of many insects, like the butterflies, moths, flies, 
bees and beetles, differ so from the adults that there is no resemblance 
whatever between the two. These insects pass through at least four 
stages, the egg, larva, pupa and adult, each differing in form from the 
other. For this reason their metamorphosis is said to be complete. 

The Egg 

The egg is the first stage in the development of any insect. The eggs 
of some insects, like the plant-lice, remain in the abdomen of the mother 
until the young are fully developed and hatched. Insect eggs vary 
greatly in form, as can be seen by referring to the figures given in the 
Colored Plates. 

The Larva 

The larva is the form of an insect immediately following the egg. It 
is then in the stage of growth, and many of our common insects damage 
crops more severely during this period of their lives than at any other 
time. Larvae differ greatly in form in the different orders. The larvae 
of moths and butterflies are called caterpillars; those of flies are called 
maggots; those of some beetles are called grubs and others worms. 
Caterpillars are often called worms also. The legless larvae of bees, 
wasps and related insects are sometimes called grubs. 

The Pupa 

The pupa is the third or resting stage. The larva becomes a pupa 
when it has completed its growth. In this stage the insect has very little 
or no power of movement, being unable to do more than wriggle the tip 
of the abdomen at most. The pupa of a butterfly or moth is called a 
chrysalis; the hardened larval skin within which the pupa of some two- 
winged flies is formed is termed a puparium. 

The Adult 

The adult is the fourth and final stage in an insect's development. 
No further growth takes place after this stage is reached. Only enough 
food is taken by the adult to sustain life ; in fact some adults do not feed 
at all, their mouth parts having been lost through disuse. The prin- 
ciple function of the adult is that of reproduction. 

The Integument 

The skin or integument of an insect is composed of a tough, horny 
substance called chitin (pronounced ki-tin). At certain periods dur- 
ing the larval stage this becomes so hard that it cannot stretch and soon 
becomes too small for the growing insect. In the meantime a new skin 
is forming underneath the old one, which splits open. The insect then 
frees itself from its old coat. This process is called molting. The new 
skin is at first soft and stretches to accommodate the increasing size of the 
insect. Soon, however, it becomes hardened and must in turn be cast off. 
Thus, in the course of their development insects shed their skins several 
times. After reaching the adult stage molting ceases and all growth 
stops. 

30 



Insects in General 
CLASSIFICATION 

The insects that injure agricultural crops can be roughly grouped 
into two classes : those that feed upon the roots and underground parts of 
plants, or "root feeders;" and those that feed upon the leaves and other 
parts of plants above the ground, or "leaf feeders." 

Each of these groups can in turn be divided into two other classes: 
insects which bite their food, or "biting insects," and those which suck 
their food, or "sucking insects." 

Both classifications are most important from the viewpoint of insect 
control. 

The mouth parts of the biting insects consist of an upper and lower 
lip between which are two pairs of jaws with which portions of the food 
plant are bitten out and masticated. Attached to these jaws are slender, 
jointed organs used in guiding the food to the mouth or as sense organs. 

The mouth parts of sucking insects are modified into a long, jointed 
tube or beak and several hair-like bristles which are enclosed within it. In 
feeding, the beak is placed against the surface of the plant while the 
bristles or piercing organs are forced into the tissue. The plant juice is 
then sucked up through them by a pumping motion of the mouth. 

METHODS OF CONTROL 

There are two general methods of insect control, the cultural or 
natural method, and the artificial method. 

The natural method consists of handling the soil or the crop in 
such a way as to prevent or reduce insect injury, and in fighting injurious 
insects with their natural enemies. 

The artificial method consists of the application of any substance 
to a crop for the purpose of killing attacking insects or making the plants 
so distasteful to them that they will not feed upon them. 

Natural Methods of Control 

Application of the natural methods of control depends largely upon 
the habits and life history of the insect to be controlled. For example, 
in the case of the grasshopper we know that its egg stage is passed in the 
ground during the fall and winter. Fall plowing, harrowing and discing 
will kill the grasshopper in the egg stage. 

Crop Rotation 

Crop rotation is one of the principal factors in insect control. Many 
insects feed upon only one crop or those closely related botanically. 
It is evident, therefore, that if the same crop is planted on a field for 
several years in succession the insects attacking it are likely to accumu- 
late in and about it until serious damage results. The length of rotation 
necessary to insure against injury by an insect or other crop pest, depends 
upon the pest in question. For example, the corn root worm can be con- 
trolled by alternating corn with any other crop ; while white grubs and 
wireworms require a three or four year rotation; and the sugar beet 
nematode a much longer rotation. 

Other insects deposit their eggs upon certain crops or in the soil 
where these crops are growing or have grown. Loss can be avoided by 
following such crops with others which are not attacked by this class 
of insect. 

31 



Insects in General 

Plowing 

Many insects pass certain tender stages of their development in 
the ground or on plants in the fields. Plowing infested fields at the pro- 
per time will do much toward destroying such insects. 

Late Planting 

Injury can sometimes be prevented by timing the planting of crops 
so that they will not come up until danger of infestation is passed. 

Burning 

Many insects spend the winter in hibernation beneath the trash or 
crop refuse on and about fields. If this waste matter, dead weeds and 
grass about fence rows and ditch banks is burned during the fall or winter, 
many insects will be destroyed which would otherwise damage crops the 
following spring. 

Clean Culture 

Nearly all injurious insects fed upon wild plants before the land 
was broken up and planted to crops. If weeds are allowed to grow in 
a crop or about the fields, ditch banks, fences or roadsides, they attract 
these insects to the vicinity. After the wild food plants have been 
destroyed, the insects turn their attention to crops and much damage 
results. Clean cultivation is always profitable from the standpoint of 
insect control as well as for other reasons. 

Artificial Method of Control — Insecticides 

What substance to use and how to use it in artificial control depends 
upon whether the insects are biting or sucking insects. There are 
two general classes of insecticides, those which kill after they are eaten 
(stomach poisons), and those which kill by coming in contact with the 
insects (contact poisons). The first is used against insects which bite 
their food, and the second against those which suck it. 

Control of Biting Insects 

In the control of most biting insects poisonous substances such as 
Paris green and arsenate of lead are used. These are applied either as a 
spray mixed with water or dry. In the latter case the poison is mixed 
with low grade flour, air slaked lime or some other fine powder and dusted 
onto the crop. ^ The jDoisons'are often mixed with some substance which 
the insects will eat, and this poisoned bait, as it is called, is scattered 
over infested fields. 

In the control of some biting insects it is necessary to kill them while 
in the egg stage. This is done by spraying with oils which can be mixed 
with water or with lime-sulphur wash (See page 115). These oils are 
petroleum products rendered soluble by the addition of vegetable oils 
and are known by the trade name of "miscible oils." 

Many biting insects devour the entire leaf in feeding, while others 
feed on the under side of the leaves only, eating all but the upper surface. 
In applying stomach poisons it is very essential that the location of the 
insects while feeding be known. If they feed on the under side of the 
leaves the sprayer must be adjusted so that the poison is applied to the 
lower surface. 

32 



Insects in General 



Sprayers 



Sometimes arsenical poisons burn the leaves of plants, especially 
if the application is heavy. This is due to free arsenious acid in the 
material used. The addition of a little quick lime to the water in which 
the poison is mixed will prevent this burning. When lime has been 
added the solution must be carefully strained to remove particles of lime 
which would otherwise clog the nozzles. 

Control of Sucking Insects— Contact Poisons 

In the control of sucking insects the contact poisons kill the insects 
either by corroding their bodies or by clogging their spiracles, thus 
causing strangulation. Black-leaf 40 (See page 114), kerosene emulsion 
(See page 114), the so-called insect powders and soluble oils are standard 
remedies for sucking insects. As the name implies, these substances 
must come in actual contact with the insect to kill it. 

Repellents 

A repellent is any substance the presence of which on plants makes 
them so distasteful to insects that they will not feed upon them. Mix- 
tures containing tobacco preparations or soap, especially whale oil soap, 
are effective as repellents. 



SPRAYERS 



A. TRACTION SPRAYER 



For field use any one of the many makes of traction sprayers (Fi£ 
I, Page 33) is recommended. 




Fig. i. A Good Type of Traction Sprayer for Field Use 
33 



Sprayers 

Such a machine should embody the following features: 

A. A tank of sufficient capacity to permit of spraying large fields 
without having to fill it in the center of the field. A tank holding 50 
gallons is large enough for practical purposes. 

B. A revolving agitator within the tank to keep the poison in 
suspension. 

C. A force pump to maintain a pressure at the nozzles in order to 
produce a fine mist-like spray. This pump should be driven by the 
wheels of the sprayer. 

D. A pressure gauge. 

E. A large air chamber. 

F. An adjustable safety valve to prevent bursting the rubber hose 
connections. 

G. An adjustment whereby the machine can be adapted to variable 
distances between rows without changing piping, hose connections or 
nozzles. 

A means of adjusting the wheels to varying widths of rows. 

CARE OF SPRAYER 
Remove Rust Scales 

There are certain soluble acids in Paris green which act upon the iron 
parts of the sprayers, especially the iron piping. This action produces 
large quantities of rust which falls away from the pipe in scales. These 
scales will clog the nozzles unless the piping and other metal parts are 
thoroughly cleaned. 

Remove Dry Paris Green 

There is always some Paris green left in the piping, tank and nozzles. 
This is apt to cause the same trouble when you start the sprayer as the 
rust scale mentioned. The barrel, or whatever kind of tank there is on 
your machine, should be thoroughly cleaned. 

Repair Hose Connections 

Be sure that all hose connections are in good repair. 

Clean Nozzles 

Often times the nozzles become clogged with dry Paris green. There- 
fore all nozzles should be taken apart and thoroughly cleaned. 

Examine Pump 

The pump is one of the most important parts of a sprayer. Too 
much pains cannot be taken in seeing that the pump is in perfect con- 
dition. Remember that the pump will not work properly if not properly 
packed. 

Examine Valves 

Next to the packing, the valves are most important. A steady 
pressure cannot be maintained if the valves are not in perfect condition. 

34 



Sprayers 

Glean Relief Valve 

The relief valve which regulates the pressure should be examined, 
since, if this fails to work, the hose connections are very apt to be blown 
off. 

Neckyoke and Eveners 

Most beets are planted 18 or 20 inches apart or 16 and 24 inches. 
In either case three rows of beets should be between the wheels and the 
wheels 60 inches apart. The eveners and neckyoke should be 60 inches 
long, so that the horses walk in front of the wheels. Less damage will 
be done to the crop from broken leaves and crushed crowns if your 
machine is equipped in this way. 

Setting the Nozzles 

The nozzles should be so placed as to make it possible to spray thor- 
oughly all surface between the end nozzles. There are so many styles of 
nozzle equipments and frames that it would require too much space to 
explain in detail the setting of all. Let it be sufficient to say that four 
single nozzles should not cover more than 5 rows of beets and 6 single 
nozzles 7 rows. If the double nozzles are used, 4 pairs will cover 8 rows 
and 6 pairs 12 rows. In spraying very small beets the nozzles should 
be placed directly over the rows. 

Testing the Pump 

Before attempting to do any spraying, test the spray pump thor- 
oughly. The pressure regulates the kind of spray your machine throws 
(fine or coarse), also the amount of water applied to an acre of ground. 
Eighty pounds pressure produces the fine mist-like spray required 
for best results. 

Test Your Sprayer 

It is the poison applied to an acre of beets and not the water which 
kills the worms. Quick and satisfactory results are secured by the use 
of 4 pounds of Paris green per acre. Unless you know how much water 
your sprayer applies to an acre, you cannot know how much poison to 
use in a tank of water. For example, if a sprayer equipped with 4 double 
nozzles and producing a pressure of 80 pounds will cover an acre with 50 
gallons of water, you should mix 4 pounds of Paris green with 50 gallons 
of water. If the pressure falls very much below 80 pounds, less water 
will be applied to an acre and more Paris green will have to be added to a 
50-gallon tank of water. 

To test your sprayer fill the tank with water, put the pump in gear, 
then drive along the road and measure the distance traveled in discharg- 
ing all of the water through the nozzles. Multiply this distance, meas- 
ured in feet, by the width of the number of beet rows you spray; say 5 
twenty-inch rows or 8.3 feet, and divide this by 43,560, which is the 
number of square feet in an acre. This will give you the part of an acre 
you spray with one tank of water. Many failures in spraying are due 
to using too little poison, and much loss in money results from using too 
much. Avoid this by testing your machine. From the above you can 
determine the amount of Paris green to use with a tank of water to 
apply the 4 pounds per acre. 

35 



Sprayers 



KNAPSACK SPRAYER 




For use in gardens or 
for spraying berry 
bushes and ornamental 
shrubs, the knapsack 
sprayer (Fig. 2, Page 
36) is very convenient. 
This sprayer can be 
placed on the ground or 
carried as shown in the 
figure. Where the gar- 
den or the number of 
plants to be sprayed is 
small this sprayer is not 
so well adapted to the 
work as the hand 
sprayer. 



Fig. 2. Knapsack Sprayer 



HAND SPRAYER 

The hand sprayer (Fig. 
3, Page 36) is suitable for 
spraying house plants, or a 
very small fruit or vegeta- 
ble garden. It can also be 
used to apply repellents to 
live stock. Where one has 
only occasional use for a 
sprayer to spray a few 
plants this type is recom- 
mended because of its small 
cost. 




Fig. 3. Hand Sprayer 



36 



Sprayers 



Paris Green 



The accompanying picture (Fig. 3-a) illustrates a home-made spray- 
er, costing approximately $25.00. This machine was successfully used 
during the 1919 growing season in the Fort Collins, Colorado district. 
Any hand-power spray pump may be used. 



A HOME-MADE SPRAYER 




Pig-. 3-a. A Home-made Sprayer 



CAUTION 

Since Paris green is a poison, due care should be exercised in 
handling it. 

Be careful not to get Paris green on the hands, face, or other 
parts of the body, or to rub the face or body with the hands if any 
of the green should get on them. The safest plan is to wear gloves. 

The poison is absorbed into the pores of the skin and causes 
a severe rash or breaking out. This absorption is more rapid 
when one is perspiring. 

Inhaling the dry poison may cause local poisoning of the 
nasal passages. 

Long continued handling of Paris green with bare hands may 
result in systemic poisoning which is accompanied by typical 
internal arsenical poisoning symptoms. 

The average person will become poisoned locally only after 
long and continuous contact with Paris green, but some individ- 
uals are much more susceptible than others. This susceptibility 
cannot be determined beforehand, hence the increased need for 
caution. 

In measuring Paris green use a long handled dipper. 

Always use a wooden paddle for mixing it. 

Destroy all cans or paper containers in which Paris green is 
received, after emptying them. Children may be poisoned by 
playing with them. 

37 



Root Feeders Cutworms 

CHAPTER II 



ROOT FEEDERS 

Taken as a class, those insects which inhabit the soil and feed upon 
the roots and other underground parts of plants are among the worst 
enemies of field, orchard and garden crops. 

Living and feeding, as they do, below the surface of the ground the 
greater part of their lives, the root feeders are seldom observed at work in 
the field. 

The effect of injury by root feeders upon the leaves and other visible 
parts of plants is often attributed to many causes but the right one, and its 
association with the insect is often not suspected until much damage has 
been done, if at all. 

Their subterranean habits, together with ' he rapidity with which some 
forms multiply, and the ease with which others are disseminated over 
large areas, make them, with few exceptions, extremely difficult to 
control. 

Furthermore, the study of the habits, life history and control of many 
root feeders is attended by peculiar difficulties, because of which our knowl- 
edge of them is often so meager that we are unable to apply effective means 
of control when some insect of this class suddenly appears in damaging 
numbers in our fields. 

Probably the best known and most destructive root feeders are the 
cutworms, whi e grubs, wireworms, corn root-worms, the corn root-louse 
and the sugar beet root-louse. To this may be added the sugar beet nema- 
tode and other closely related eelworms. 

A. BITING ROOT FEEDERS 

(Cutworms, White Grubs, Wireworms) 

1. CUTWORMS 

The name "cutworm" is applied in a general way to all of the hair- 
less larvae (caterpillars) of a group of moths or millers called "owlet 
moths," from the fact that they fly mostly at night and have eyes that 
shine in the dark. 

Probably no other insects are more dreaded irt those sections where 
they cause large annual crop losses, than are the various cutworms. 
Like the evil gnomes of old, who sallied forth on moonless nights to 
wreak vengeance upon some hapless wayfarer, the cutworms come forth 
from hiding, and, under cover of darkness, despoil the farmers' crops; 
or, like the "sappers" of an invading army, these invaders of our fields 
tunnel from plant to plant, leaving a trail of death and destruction in 
their wake. 

NATURE OF INJURY 

If, in walking through a beet field, dead and wilted plants are seen; if 
stools of grain in grain fields are dying or the stand is becoming thin; or 

38 



Cutworms 

if alfalfa starts very slowly or makes an indifferent growth in the spring, 
the fields should be examined for cutworms. 

If cutworms are causing the injury the dead and wilted beets or dying 
stools of grain will be found cut off at the surface of the ground, or just 
below it. Should these plants still be attached to their roots, there being 
no evidence of their having been partially gnawed off, cutworms are not 
responsible for the plants dying. In case the plants have been killed for 
some time the dead and dried leaves may have been blown away, leaving 
the ground bare. In this case the stubs of the plants will be found if the 
soil is removed to a depth of one-half inch or so. 

When the slowness in starting or indifferent growth of alfalfa is due 
to cutworms many new shoots will be found wilted and dead. These 
will be gnawed off near the crown of the plant. As in the case of beets 
and grain, shoots that are not at least partially gnawed off have not been 
killed by cutworms. 

While the foregoing is usually sufficient evidence that cutworms are 
or have been injuring a crop, yet the real proof is in finding the worms. 

WHERE TO LOOK FOR THE WORMS 

Most cutworms, like the moths which produce them, are nocturnal 
in habit. They lie hidden beneath trash or just below the surface of 
the soil during the day, coming forth toward dusk and during the night 
to feed. When very numerous and during cloudy, damp days, they 
sometimes move about quite freely in the early part of the day. 

In infested fields the worms will usually be found buried in the soil 
near some plant which has been recently cut off. In alfalfa they will be 
found buried near the crowns of the plants or under the trash scattered 
over the field. Many times they accumulate under boards and other 
objects lying on the surface of the ground. Careful watch should be 
kept for worms before planting as damage can best be avoided by de- 
stroying them before the crop is sown. 

METHODS OF CONTROL 

Poisoned Bait; Kansas Mixture 

The best known method of killing cutworms is the use of poisoned 
bait. A poisoned bran mash known as Kansas Mixture seems to give 
the best results. The formula for use against cutworms is as follows : 

20 lbs. bran or shorts; 

1 lb. Paris green; 

2 qts. molasses (any cheap grade or beet molasses) ; 

2 lemons or oranges (lemons preferred) ; 

3 gals, water. 

How to Make Kansas Mixture 

Thoroughly mix the bran or shorts and the Paris green dry. Chop 
the lemons or oranges, rind included, very fine. If a food chopper is 
available, use this. Add the molasses and chopped fruit to about one- 
half of the water and stir until the molasses is dissolved. Add this 
mixture to the bran and Paris green and mix evenly. The rest of the 
water should then be added a little at a time, stirring the mixture while 
doing so, and until the whole mass is evenly moistened. When this 

39 



Cutworms 

has been done the bran should be just moist enough to stick together, 
but not so wet that it will not crumble freely. In this condition it 
can be evenly and thinly scattered over the field to be treated. 

How to Apply the Bait 

The poisoned bait should be scattered broadcast over the infested 
field. This can be done by hand, care being taken to prevent large lumps 
from being left in the field unbroken. If the bait is thinly and evenly 
scattered there is no danger of poultry or livestock being poisoned by 
eating it. If properly scattered a mixture made of 20 pounds of bran 
will cover 2| acres. 

Time to Put Out the Bait 

Since the cutworms, as a rule, do not begin feeding until late after- 
noon or early evening, the bait should not be spread until about sun- 
down. If spread earlier in the day, especially if the weather is hot and 
dry, the bait will become dried out before the worms begin feeding. 
In this case the results are apt to be disappointing. It is claimed that 
cutworms feed much more freely on shorts when dried out than on bran.* 

Treating Fields Before Planting 

Infested fields should be treated with poisoned bait before plant- 
ing. If properly applied one application of Kansas Mixture is sufficient 
to rid a field of cutworms. After being treated in this manner a field 
can be planted with safety. 

Other Poisoned Bait 

Freshly cut clover or alfalfa thoroughly sprayed with Paris green 
and water (1 lb. Paris green to 25 gallons water) and spread over infested 
fields is often substituted for Kansas Mixture. It is very doubtful if 
this is as satisfactory as the poisoned bran mixture. This method 
should be avoided because of the danger of poisoning live stock. 

Rolling 

Rolling is sometimes recommended for killing cutworms. How- 
ever, it is a doubtful method and one which is very apt to be disappoint- 
ing in its results. Unless the surface of the field is very smooth and 
compact, rolling is a waste of time for this purpose. If done at all it 
must be done at night when the worms are moving on the surface. Gen- 
erally speaking, rolling is not to be recommended. 

Discing 

Discing is even less effective than the roller, for destroying cut- 
worms, and is not recommended. 

Plowing 

Deep fall plowing will often give good results, especial-ly if the soil 
is thoroughly disced before plowing and the surface well worked down 
afterward. 

Replowing of infested fields in the spring, if the plowing is deep 
and the surface thoroughly worked afterward, has given good results 
when the season is not too far advanced for the planting of early matur- 
ing crops. 

*E. H. Streckiand, "Control of Cutworms in the Prairie Provinces," Circular No. 6. Department of 
Agriculture, Dominion of Canada (1916). 

40 



Cutworms Western Army Cutworm 

Late Planting 

Late planting may sometimes be resorted to as a means of prevent- 
ing loss by cutworms. However, before resorting to this means the 
best plan, if one is in doubt as to the identity of the particular cutworm 
in question, is to send some of the worms to the State Entomologist, 
to the Experimental Department of The Great Western Sugar Company, 
Longmont, Colorado, or to some one else familiar with these insects and 
qualified to give advice regarding them. If this is done much time and 
many dollars may be saved. Before resorting to late planting read 
carefully what follows about the different species of cutworm, especially 
the Pale Western Cutworm. 

(a) WESTERN ARMY CUTWORM 

(Figs. 1, 2, 3 and 4, Plate I, Page 11) 

The name "western army cutworm" has been applied to this species 
because under favorable conditions it becomes very numerous and at 
such times travels en masse in much the same way as the true army worms. 

It is also often called the "alfalfa cutworm," because of its prefer- 
ence for this crop. In Northern Colorado it seldom injures crops unless 
they are planted on recently broken alfalfa land or in fields adjoining 
infested alfalfa fields. 

DESCRIPTION 
The Worm 

Figure 1 , Plate I , Page 1 1 represents a full grown western army 
cutworm, natural size. This worm is marked with various shades of 
brown above, while the lower part is a dirty white. There are usually 
several dark spots on each segment of the body. Each of these bears 
a short, stiff bristle. These bristles are not always easily seen with the 
naked eye. Some individuals are much darker than in the figure, while 
others are lighter. This is the most common cutworm in alfalfa fields. 

The Pupa 

Shortly after the cutworm becomes full grown it burrows into the 
soil to a depth of about two inches. The next few days are spent in 
wriggling and twisting about, making a cosy cell in the soil. 

Rapid changes now begin to take place in the worm. It gradually 
shortens and changes from its original color to a dirty, whitish yellow. 
The skin, which has become much shrunken and wrinkled, now cracks 
open, exposing a yellowish brown object within. A few more twists 
and turns and the pupa (Fig. 2, Plate I, Page 1 1) frees itself from the 
skin which covered the worm. 

The Moth 

The change from worm to pupa is only the beginning. During the 
next two or three weeks nature is at work within the brown walls of 
the pupa forming a body, legs and wings and hundreds of feather-like 
scales (Fig. 4, Page 42) to cover them. When all is complete, our ugly 
cutworm has taken on still another form. The brown walls of the pupa 
burst open and after much pulling and straining the moth emerges. 
At each side of its body hang two crumpled objects. As we watch these 
they begin to expand and lengthen. In a very short time they have 

41 



Western Army Cutworm 

developed into delicately colored wings. The cutworm has now reached 
the fourth or perfect stage, the moth. 

These moths (Fig. 3, Plate I, Page 11) are easily recognized by the 
light stripe on the forward edge of the fore wing. A few individuals 
lack this stripe, the fore wing being colored as shown in Figure 4, Plate 
I, Page 11. 




Fig. 4. 



LIFE HISTORY 



Scales from Wing of Moth of Western Army Cutworm, 
highly magnified 



Our knowledge of the life history of the western army cutworm is 
incomplete. However, recent investigations conducted by Prof. R. A. 
Cooley, Entomologist of the Montana Experiment station,* have de- 
termined some of the more important points. 

Prof. Cooley and his associates draw the conclusion that the west- 
ern army cutworm is single brooded in Montana. This is probably 
true of Northern Colorado as well. 

The eggs are deposited, so far as is known, on bare ground, on clods 
of earth, stubble and dead roots on the surface of the soil. Each female 
moth is capable of laying several hundred whitish, ribbed, and more 
or less globular eggs similar to those which are shown much enlarged 
on Plate I, Page 11, Figures 11 and 12. The greater part of the egg 
laying is done during September and October. 

The eggs hatch in about ten days under ordinary conditions, but a 
longer time is required if the weather is cool or the season advanced 

*" Observations of the Life History of the Army Cutworm." Journal of Agricultural Research, Vol. 
VI. No. 23 (1916). 

42 



Western Army Cutworm 

when they are laid. The young worms feed during the fall until winter 
comes on. As a rule little or no damage is noticed as a result of this fall 
feeding. With the coming of cold weather the worms become dormant, 
in which condition they remain until the coming of warm weather in the 
spring, when they resume feeding. 

In seasons of normal temperatures the worms feed until about April 
15th or May 1st. If the season is cold and backward the feeding period 
is prolonged. Under such conditions the worms have been known to 
feed until well into May. 

Advantage can be taken of our knowledge of the feeding 
habits of this worm in the sowing of our crops. In case we have 
an infested field it can safely be planted to an early maturing crop by 
waiting until the worms have ceased feeding, which is normally about 
the middle of April in the latitude of Denver. Farther north, planting 
should be delayed until about May 1st to 10th. 

The moths begin to appear in numbers about June 15th. From 
this time until the fore part of July they are most abundant. They 
often become a nuisance in dwellings, causing much annoyance by 
flying about the lamps. When very numerous the moths will be found 
under any object which affords concealment during the day. Old gar- 
ments hanging on the sides of out-buildings seem to be favorite hiding 
places. The moths live until fall, when egg laying begins. 

NATURAL ENEMIES 

There are a number of parasitic and predacious insects which prey 
upon the western army cutworm. The most important of these are: 
Ichneumon-flies, Braconids, Chalcis-flies and ground beetles and certain 
species of digger-wasps. Several species of birds destroy great numbers 
of cutworms also. 

Ichneumon-flies, Braconids and Chalcis-flies sting their eggs into 
the cutworms, using for this purpose a long slender organ called an 
ovipositor. This ovipositor is located at or near the tip of the abdomen. 
After the eggs have been placed in the body of the cutworm the little 
grubs hatch and immediately begin feeding. These grubs subsist 
upon the body fluids and fatty substances of the cutworm but do not 
destroy its vital organs until they are fully grown. 

Ichneumon-fly 

The larva of the Ichneumon-fly 10 (Fig. 5, Plate I, Page 11) does 
not kill the worm, which changes into a pupa before the parasite's work 
is finished. The moth never develops in a parasitized pupa, however, 
for the pupa is killed by the parasite, which gnaws its way out when it 
is fully developed. Instead of a moth coming forth to lay more eggs to 
infest our fields, the wasp-like Ichneumon-fly emerges, and if a female 
it deposits its eggs in other cutworms, thus carrying on the good work 
of ridding our fields of these pests. 

Braconid , 

The larvae of the Braconid 2 (Fig. 6, Plate I, Page 1 1) kill the worm 
before it changes to a pupa. When fully grown the grubs gnaw their 
way out of the worm and proceed to spin about themselves little silken 

( 10 - 2 ) See explanation of "'Reference Figures." page 2. 

43 



Western Army Cutworm 

cocoons (Fig. 7, Plate I, Page 11) in which their development is com- 
pleted. These cocoons are sometimes fastened to the dead worm, 
sometimes to grasses or other plants, where they cling in clusters. 

Chalcis-fly 

The little Chalcis-fly 4 (Fig. 8, Plate I, Page 11) is one of the most 
interesting parasites which attack the cutworms. The parasitized 
worms die before changing into pupae. A single worm killed by this 
parasite has been known to contain over 2,000 of these little flies. The 
parasites complete their development in the dead worm. Figure 4, 
Plate IX, Page 27 shows a parasitized worm just before the emergence 
of the parasites, the pupa of which completely fill the skin of the cut- 
worm and can be seen through it as little oval bodies. 

Digger-wasp 

The digger-wasp 6 (Fig. 18, Plate VI, Page 21) is another very in- 
teresting natural enemy of cutworms. The figure represents one of these 
insects carrying an army cutworm to its burrow. So interesting are 
their habits that the writer is giving the story of the capture and sub- 
sequent entombing of a cutworm by a digger-wasp. 

On warm days in early summer these blue-black wasps can be seen 
hurrying over the ground, in and out of every hole, under every clod 
and into every possible place where a cutworm could hide. In its search 
many short flights are made and when running the wings are jerked 
nervously, while every movement of the hunter is indicative of the 
greatest haste. 

When a cutworm is found it is immediately paralyzed, apparently 
by being stung. This does not kill it but renders it helpless, in which 
condition it remains until destroyed by the larva of the wasp. 

The next act in this tragedy of nature is the finding of a suitable 
place to leave the worm while a site for the home of the young wasp is 
found. Always, so far as observed, the worm is left on some high place, 
such as the top of a large clod of earth or in a fork of some plant an inch 
or two above the ground. 

Dame wasp (for it is always the female that catches the cutworms) 
does not believe in the old adage, "Never catch a bird until you have a 
cage for it," as the worm is always secured before the burrow is dug. 
The worm having been left in some place of prominence, the search for 
a suitable location to dig a burrow begins. Mrs. Fossores (for this 
is one of her names) does not consider "any old place" good enough 
for a home for her young. One wasp was seen to start seven burrows 
before finding a place entirely to her liking. The eighth location proved 
satisfactory and the burrow was completed. Several of the unsatis- 
factory attempts were made where the soil was soft and the digging easy; 
however, an easy job did not seem to be what the wasp was looking for. 
The location finally selected was in a hard beaten pathway where the 
digging was very difficult. Thirty minutes were consumed in the con- 
struction of the burrow. The wasp rested but once during this period 
and then for but a very short time, when she lay flattened out on the 
warm soil in the sunshine. 



C 4 - 8 ) See explanation of "Reference Figures." page 2 

44 



Western Army Cutworm Pale Western Cutworm 

When the nest was completed the wasp wandered about for several 
minutes and finally went to the worm, grasped it by the throat and 
carried it in almost a straight line to the mouth of the burrow, where 
it was laid with its head toward the opening. She then entered the 
burrow, turned around, came out, and grasping the worm, backed into 
the burrow again, dragging it after her. After a few seconds, during 
which time the egg was fastened to the worm, the wasp reappeared, 
turned its head away from the mouth of the burrow, and, standing on 
her four hind legs, clawed dirt into it with her front feet. Every little 
while she turned around to ram the dirt into the opening with her head. 
This was continued until the mouth of the burrow was completely filled. 
The surface of the soil was left in such a condition that it was only with 
the greatest difficulty that the writer could locate the burrow. 

The egg, shown fastened near the head of the worm in Figure 17, 
Plate VI, Page 21, gradually changes into a maggot. The forward end 
of this maggot, which contains the mouth, is long and pointed and during 
the entire feeding period remains embedded in the body of the worm. 
As the larva increases in size the worm shrinks until, when the grub is 
fully grown, nothing but its empty skin remains, as shown in Figure 16, 
Plate VI, Page 21. When the young wasp has exhausted its supply of 
food its head is withdrawn from the empty skin of the worm. 

The next day or so is spent in lining its burrow with a silken cocoon, 
within which the grub changes to the pupa and finally into the adult 
wasp. 

Birds 

Birds are among the most effective natural checks of cutworms. 
The meadow lark is probably one of the most valuable, its food in May 
being about 24% caterpillars, the greater part of which are cutworms. 
Blackbirds of all species, and robins, destroy large numbers of cutworms, 
as do many other ground feeding species. 

(b) PALE WESTERN CUTWORM 

(Figs. 9, 10, 11 and 12, Plate I, Page 11) 

The pale western cutworm n is a western species which until 
1911 was not known as seriously injurious. Reported outbreaks have 
all occurred in the Great Plains and Rocky Mountain areas of the United 
States and the prairies of Western Canada. 

Unlike the western army cutworm, this species does not occur in 
alfalfa to any extent. Fall grain, crops planted on weedy fallow land 
and those following grain are most apt to be injured. Seldom are crops 
following cultivated crops injured unless they are adjacent to infested 
fields. This is especially true of crops following sugar beets and potatoes. 

DESCRIPTION 
The Worm 

The full grown worm (shown natural size, Fig. 9, Plate I, Page 11) 
is a dirty, pale gray color. After eating its fill of green food it takes on 
an olive tinge. The head and part of the first segment of the body back 
of it are light brown. There are usually two dark lines on the head as 



( 12 ) See explanation of "Reference Figures." page 2. 

45 



Pale Western Cutworm 

shown in the figure. The small dark spots on the segments of the abdo- 
men, each bearing a short stiff bristle, are usually plainly visible. 

Just beneath the skin of the back is an organ which fulfills the 
offices of the heart in the higher animals. This shows as a dark line 
in the center of the back running nearly the whole length of the worm. 
If watched closely it will be seen to pulsate in true heart fashion when 
the worm is alive. 

The Pupa 

The pupa resembles that of the western army cutworm so closely 
that Figure 2, Plate I, Page 11, will suffice for both. Aside from some 
minor structural differences the only difference is in the size. The pupa 
of the species under consideration is slightly smaller than that of the 
western army cutworm. 

The Moth 

Figure 10, Plate I, Page 1 1 represents the moth, natural size. The 
whole insect is lighter than the moth of the western army cutworm. 
The colors are chiefly delicate shades of tan and brown. These moths 
fly more freely during the day than those of the preceding species. On 
warm afternoons in fall they have been seen feeding on the blossoms of 
"rabbit brush" in quite large numbers. 

LIFE HISTORY 

The life history of the pale western cutworm is essentially the same 

as that of the western army cutworm. The only important differences 

[ are in the dates when feeding ceases and the changes from worm to pupa 

[ and pupa to moth take place. For a description of how and where these 

[ changes take place read those parts of the discussion of the western 

army cutworm under the heads "The Pupa" and "The Moth' "(Page 41). 

This cutworm is single brooded in Northern Colorado. The eggs, 
shown very much enlarged in Figures 11 and 12, Plate I, Page 11, are a 
little less than fa of an inch in diameter. The eggs are laid during 
September and October, and so far as known are deposited either in 
cracks in the soil, on lumps of soil or on the surface of the soil. Seldom, 
if ever, are they deposited on green plants. Dry, fallow land and stubble 
fields are ideal locations for egg laying. 

During open, warm falls some eggs may hatch before winter sets in, 
but field observations indicate that the greater part of the eggs do not 
hatch until spring. As soon as hatched the worms begin feeding and 
continue to feed until the last of June or the first or second week of July. 
Because of this late feeding habit late planting cannot be re- 
sorted to as a means of preventing loss, as no profitable field 
crop can be planted at this late date. 

The worms remain in their earthen cells for two or three weeks 
before the change to the pupa takes place. In about four weeks more 
the moth emerges. 

NATURAL ENEMIES 

Little is known of the natural enemies of the pale western cutworm. 
In all probability it is held in check by some of the same parasitic and 
predacious insects and birds as the western army cutworm. 

46 



Variegated Cutworm 

(c) VARIEGATED CUTWORM 

(Figs. 7 and 15, Plate VII, Page 23) 

This is one of the most universally distributed of all cutworms. It 
is known over practically the whole agricultural world with the possible 
exception of Africa. At one time or another damaging outbreaks of 
this worm have occurred in nearly every part of its range. While, so 
far as the author knows, no serious outbreak has occurred in the sugar 
beet growing sections of the West which come within the scope of this 
Bulletin, yet it is always present in our fields and may at any time appear 
in such numbers as to do considerable damage. 

This worm is a very general feeder, attacking almost any green 
plant. It seems to prefer cultivated plants, and feeds sparingly upon 
weeds, grasses and grains. 

NATURE OF INJURY 

The feeding habits of the variegated cutworm differ in some respects 
from those of the preceding species. In California it is reported as 
damaging young sugar beets in April.* At this time the worms spent 
the day buried in the soil, coming out to, feed during the night and early 
morning. The beets were eaten off near the surface of the ground in true 
cutworm fashion. During the same season a later brood of worms fed 
upon the leaves, entirely stripping the plants of foliage. The roots were 
also damaged to some extent. Large numbers of these worms have been 
observed in Northern Colorado on the third cutting of alfalfa. 

METHODS OF CONTROL 

While the author has had no experience in the control of this cut- 
worm, it would seem that during the early part of the season, before 
the worms have acquired the climbing habit, the poisoned bait so suc- 
cessfully used against the western army and pale western cutworms 
would be equally successful in the control of this species. 

In the case of later broods or when the worms are feeding upon the 
leaves, spraying with Paris green will give satisfactory results, according 
to Mr. G. E. Bensel.* In his work in California Mr. Bensel used 2 pounds 
of Paris green to 50 gallons of water. To this about 1 lb. of molasses 
was added to make the poison adhere to the leaves. Two or three 
applications were required, at a cost of about 90 cts. per acre, to check the 
worms. A traction sprayer should be used in order to secure an even 
application and an economic use of the poison. 

Large lantern traps were also used to catch the moths in Ventura 
Co., California, with very satisfactory results. 

DESCRIPTION 
The Egg 

The eggs resemble those of other cutworms. They are deposited 
in clusters of from a few to as high as 50 or 60 on the twigs of trees and 
leaves of various plants. 

*G. E. Bensel. "Control of the Variegated Cutworm in Ventura County, California." Journal of 
Economic Entomology, Vol. 9. No. 2 (April, 1916). 

47 



Variegated Cutworm White Grubs 

The Worm 

The worm (Fig. 7, Plate VII, Page 23) is variable in color, ranging 
from a very pale to almost a dark brown. Some light individuals have 
a greenish tinge. The upper part is mottled with various shades of 
brown and in the darker worms some black. On each side is a con- 
spicuous yellow stripe and above this a dark stripe broken into a row 
of crescent spots, as shown in the figure. The most characteristic mark- 
ing is the row of yellow spots in the center of the back on the forward 
half of the body. 

The Moth 

The moth, like the worm, varies in color. The one shown in Figure 
15, Plate VII, Page 23, is of the dark type, the other extreme being very 
much lighter, while all gradations of color between the two occur. Like 
the moths of most cutworms, the adult variegated cutworm flies princi- 
pally during the night when it is attracted by strong lights. Advantage 
of this fact is sometimes taken in applying control measures. 

LIFE HISTORY 

As is likely to be the case with insects which range over so large 
a territory, the seasonal history of the variegated cutworm varies with 
the locality. It is known to pass the winter in every stage from the egg 
to the adult moth, depending upon the latitude. In Northern Colorado 
it probably passes the winter in the pupal stage or as a partly grown 
worm. There are two, possibly three, generations produced annually 
in the latitude of Northern Colorado. The damage is done largely by 
the first and second broods. The third brood, when produced, usually 
comes too late to do any great damage during the fall. However, these 
late hatched worms may hibernate over winter, in which case damage 
may be done the following spring. 

2. WHITE GRUBS 

(Figs. 19, 20 and 23, Plate I, Page 11) 

White grubs are the larvae of several species of rather robust beetles 
commonly known as May beetles or June bugs. These beetles often 
enter houses at night, being attracted by the lights. At such times 
they fly awkwardly about, their wings making a loud humming noise. 
Their flight usually ends abruptly as they collide with the wall or some 
object in the room and fall heavily to the floor. 

These insects belong to a large family, some species of which are 
scavengers, while others feed upon living plants. The latter do much 
damage to crops, especially in the Mississippi Valley and eastward. 

The Sacred Beetle of Egypt belongs to this family. This beetle 
was held in high veneration by the ancient Egyptians. It was placed in 
the tombs with their dead. The members of this group we know as 
"tumble-bugs," from their habit of rolling about large balls of dung in 
which their eggs are laid. To the Egyptians this ball was symbolic of 
the earth and the beetle of the sun. The thirty joints of the feet were 
taken to represent the days of the month. It was supposed that all of 
these beetles were males. This was taken to symbolize a race of warriors, 

48 



White Grubs 

a superstition which reached as far as Rome, where the soldiers wore 
images of the beetles as sets in their rings. 

The grubs of some species lie on their backs in the soil. This is 
responsible for a myth of the Cherokee Indians* which runs something 
like this: 

In the old days the beasts, birds, fishes, insects and plants could 
all talk and they and the people lived together in peace and friendship. 
As time went on the people became so numerous that they began to crowd 
the poor animals until they became cramped for room. Worse yet, 
man invented bows, knives, blow-guns, spears and hooks and began to 
kill the birds, animals and fishes for food and to tread upon the smaller 
creatures, such as frogs and worms, out of pure contempt. So the animals 
decided to hold a council to determine upon measures for their common 
safety. 

The bears met first. After each had complained about how man 
killed their friends, ate their flesh and used their skins for robes, it was 
decided to begin war against man at once. Some one asked what weapons 
man used. "Bows and arrows," was the answer. The bears decided 
to try fighting man with his own weapons. One bear got a fine piece of 
locust wood for the bow. Another sacrificed himself for the good of his 
friends that his entrails might be used for bow strings. But, alas, it was 
found that the bears' long claws spoiled the shot. Some one proposed 
that their claws be trimmed. This was done and the arrow flew straight 
to the mark. The leader, a large white bear, objected, saying that all 
bears needed claws in order to climb trees. "It is better to depend 
upon teeth and claws that nature gave us, for it is evident that man's 
weapons are not for us. " 

The deer held council next and decided to send rheumatism upon the 
hunter who killed one of them unless he took care to ask their pardon 
for the offense. 

Next the fishes and reptiles held council and decided to cause man to 
dream of snakes twisting about him in slimy folds or of eating decayed 
fish so that he would sicken and die. 

Finally the birds, insects and other small animals came together in 
council. The grubworm was chief of the assembly. After all had made 
complaint about the cruelties of man they began to name the different 
diseases with which he should be afflicted. As disease after disease was 
named, the grubworm became so happy that he finally shook for joy and 
fell over backward and was unable to rise but had to wriggle off on his 
back, as the grubworm has done ever since. 

When the plants heard what had been done by the animals they 
decided to defeat their evil designs. So each tree, shrub and herb, down " 
even to the grasses and mosses, agreed to furnish a cure for some one of 
the diseases. Thus came medicine. 

NATURE OF INJURY 

White grubs never appear above ground but live and feed below the 
surface. They are naturally grass-land inhabitants, being most common 
in pasture and meadow land, where they feed on the roots of the grasses. 

*"Myths of the Cherokee," Nineteenth Annual Report of the U. S. Bureau of Ethnology (1898). 

49 



White Grubs 

Sugar beets, potatoes and corn are among the field crops most seriously 
damaged. Garden truck and strawberries often suffer heavily, also. 

In the case of potatoes and sugar beets deep pits are eaten into the 
tubers and roots. If sugar beets are damaged when the plants are small 
the root is eaten off two or three inches below the surface of the ground. 
The plant, of course, wilts. If it is pulled the tip of the root at the point 
where it is eaten off will be dark in color, sometimes almost black. Wire- 
worm injury is so similar to this that the two are easily confused. Later 
in the season when the beets have attained some size they may not be 
entirely eaten off but portions of their surface will be eaten away. Beets 
attacked at this time of the year usually wilt, especially in the heat of 
the day. Such beets are easily pulled because the grubs have destroyed 
most of the smaller roots. When removed from the soil, the surface 
will be found pitted, the pits being dark in color and rough on the surface. 

The adults (beetles) of many of the injurious June bugs feed upon 
the leaves of various trees, mainly cottonwoods and willows in the beet- 
growing areas covered by this Bulletin. Injury by white grubs has been 
noted only in river bottoms where natural sod and the trees mentioned 
above are both common. Crops following sod or crops in which 
much grass was allowed to grow are most apt to be injured. 

METHOD OF CONTROL 

There is no known method by which an infested field can be freed 
of white grubs without injury to growing crops. However, measures can 
be taken which will reduce the injury or prevent future losses. 

Pasturing with Hogs 

When practical, pasturing with hogs will rid land of grubs. There 
is one drawback to this method, however. This lies in the fact that the 
giant thorn-headed worm, an internal parasite of swine, passes one stage 
of its life in certain white grubs. Hogs eating these grubs become in- 
fested and grubs eating the excrement of such animals become infested 
in turn. If no hogs have been pastured on land for at least three years, 
grubs in it will not contain this parasite, and hogs pastured on such land 
will not become infested. 

Rotation 

White grub losses can be reduced by practicing a proper system of 
rotation. Since the beetles usually deposit their eggs in fields of grass or 
small grain, sugar beets, potatoes or corn should not follow these crops in 
localities where grubs occur unless the ground is known to be free from 
them. Alfalfa, clover, buckwheat, peas and small grain are not damaged 
to the same degree as the crops mentioned above. 

Plowing 

Fall plowing, if done early, is a great help in destroying this pest. 
As the grubs burrow deep into the soil as cold weather comes on, to be 
effective, fall plowing must be done not later than October. Fall plow- 
ing is much more effective if followed by the disc or harrow. Plowing 
infested land in July or August will destroy many beetles, as the change 
from pupa to adult takes place about this time and the newly trans- 
formed beetles are easily killed. 

50 



White Grubs 

LIFE HISTORY 

The life histories of the May beetles are not very well known. Few 
records exist of the raising of beetles from the egg. In all probability 
most, if not all, of the injurious species occurring in the beet growing 
sections of the arid West have a three year life cycle. It is possible that 
the same species may complete its development in two years in the South, 
in three years in the northern tier of states, and require four in Canada. 

In general, the life cycle of the white grub is as follows : The beetles 
lay their eggs in the soil in early summer. As soon as the young grubs 
hatch they begin to feed. At this time they seem to prefer decaying 
vegetable matter, although when very numerous they are known to 
attack and damage growing crops. Feeding continues until the approach 
of cold weather, when the grub burrows deep into the soil, where it spends 
the winter in hibernation. Usually the damage done during the first 
season of the grub's life is slight. 

With the return of spring the grubs come toward the surface, where 
they begin a season-long campaign against the farmers' crops. It is 
during this second year of their lives that the grubs do the most damage. 
At this age the grub appears as in Figure 19, Plate I, Page 11. 

Again with the coming of winter the grub burrows into the soil, 
returning to the surface the following spring to feed a few weeks. The 
change from grub to pupa takes place about the first of June. After 
remaining in this resting stage for several weeks the adult beetle emerges 
from the pupa. The beetles do not leave the soil until the following 
spring, however. Digging their way out of the soil during May, the 
beetles proceed to feed, mate and deposit the eggs for another generation 
of grubs. 

Figure 23, Plate I, Page 11 represents the adult of a common white 
grub which sometimes occurs in fields in our river bottoms. 

Figure 20, Plate I, Page 11 is the grub of a small species which is 
found in newly broken alfalfa ground and is often mistaken for the young 
grubs of injurious species. So far as known it feeds only upon rotting 
vegetable matter and not upon crops. 

NATURAL ENEMIES 

The white grub is preyed upon by many birds, animals and insects, 
which materially aid in holding it in check. The U. S. Biological Survey 
has found this insect in the stomachs of 60 species of common birds. Of 
the feathered enemies of the white grub the crow and the crow blackbird 
are no doubt the most important. Both of these birds will follow the 
plow in grub infested fields and search out the grubs exposed. The 
number of grubs which a crow blackbird will eat at one time is almost 
beyond belief. It has been reported* that one bird ate 20 grubs in about 
two minutes. 

Skunks are very fond of white grubs. Meadow lands are often so 
thoroughly worked over by these animals that hardly a square yard over 
large areas does not contain one or more of the shallow holes from which 
a grub has been taken. 

*J. J. Davis, "Common White Grubs." Farmers' Bulletin No. 543, U. S. Department of Agricul- 
ture (1913). 

51 



White Grubs 



Wireworms 



Parasitic and predacious insects, while they destroy many of the 
grubs, and beetles as well, are of less importance seemingly than the bird 
and mammal enemies of this pest. In the Farmers' Bulletin mentioned,* 
Mr. Davis names two wasps, " Tiphia inornata Say., " and " Elis sexcincta 
Fab.," and a parasitic fly, " Pyrgota undata." The first two destroy 
the grubs and the last preys upon the beetles. 

3. WIREWORMS 

(Figs. 13, 14, 15, 16, 17, 18, Plate I, Page 11) 

Few boys and girls grow to manhood and womanhood on the farm 
without becoming familiar with the "snapping-beetles, " " skip-jacks, " 
or "click-beetles, " as adult wireworms are called. (Figs. 16 and 17, Plate 
I, Page 11, and Fig. 5, Page 52.) 

Many a dull moment has been en- 
livened by the acrobatic performances of 
these trim, slender bodied beetles which 
drop as if dead, when touched. With 
their legs closely folded against their 
bodies they feign death until they think 
all danger is past, when they are off for 
cover as fast as they can travel. If they 
happen to fall on their backs they will 
spring into the air several inches, turn 
over, land on their feet, and are off at 
a run. This springing is accompanied 
by a sharp snap or click, therefore the 
names "snapping-beetles" and "click- 
beetles. " 

There are over 500 species of these 
insects found in the United States. 
The larvae of many of these live in the 
decaying wood of stumps and fallen trees. 
Many others are denizens of the soil. 
Among the latter are the injurious forms. 
These are most apt to be found in pasture 
and meadow lands or wherever grass is 
allowed to grow about the fields. A few 
species are known to be predacious, feed- 
ing upon other insects and often upon their own kind. 

NATURE OF INJURY 

During the early part of the season, especially about the time the 
beets are being blocked and thinned, here and there a beet will be found 
which is apparently dying. The leaves will be wilted, many times the 
outer ones being dead and dry. When such beets are pulled they will be 
be found gnawed off an inch or two below the surface of the ground. 
The end of the beet as it comes from the soil will usually be dark, almost 

*J. J. Davis. "Common White Grubs." Farmers' Bulletin No. 543. U. S. Department of Agriculture 




Fig. 5. Adult Snapping-beetle, Alaus 

i oculatus. The larvae of this beetle 

feed upon decaying wood. 



(1913). 



52 



Wireworms 

black. This wilting of the leaves, associated with the darkening of the 
tip where it is gnawed off, are characteristic of wireworm injury; how- 
ever, the work of white grubs is very similar in the early part of the season. 

Many times beets eaten off by wireworms will throw out new roots, 
especially if the soil is moist. Such beets develop a short sprangly root 
as a rule. If the soil is dry and the weather warm the injured plants 
usually die. This results in a poor stand if the injury is severe. 

Wireworm injury to sugar beets is not so severe in the Great Plains 
States as it is farther ea'st and in California. In the latter state the 
damage is especially severe and is due to the sugar beet wireworm, which 
is very numerous in the beet fields of some parts of that state. 

This wireworm also damages alfalfa, corn and beans. 

METHODS OF CONTROL 

Because of the great similarity between the habits and life history of 
white grubs and wireworms, many of the same methods of control may 
be used against both. 

Rotation 

As already stated, wireworms are most likely to be found in abund- 
ance in pasture and meadow lands. When such lands are broken up 
and planted to field crops those least apt to be badly injured should be 
put in the first season. Row crops, such as sugar beets, corn or 
potatoes, suffer most severely on infested ground. While the 
small grains are sometimes severely injured they are not as a rule so 
badly damaged as corn and root crops. 

Short rotations in which the land is not allowed to remain in grass 
for any length of time will prevent the increase of wireworms, as the 
females prefer grass lands as places to deposit their eggs. 

Plowing 

Early fall and late summer plowing will kill many newly transformed 
beetles and pupae, especially if the surface is thoroughly worked with the 
disc or harrow. 

Seed Treatment 

Sometimes wireworms injure seed corn before it germinates, thus 
causing an almost total loss of stand in severe cases. Treating the corn 
before planting by coating it with gas tar and dusting with Paris green 
will almost entirely prevent loss, according to tests conducted by Dr. H. 
T. Fernald in Massachusetts in 1908 and 1909. 

Poisoned Bait 

Many poisoned baits have been tried, but with very little success. 

DESCRIPTION 
The Worm 

Wireworms vary in form and color as well as size. The species most 
injurious to sugar beets resemble Figure 13, Plate I, Page 11. This is 
the larva of the "click-beetle" (Fig. 16, Plate I). Figure 14, Plate I, is 
an outline drawing of the last segment of the body of this worm. The 
notch in the center is characteristic of many of our injurious wireworms. 
Figure 18, Plate I represents another species often found in our fields. 

53 



Wireworms 

The Pupa 

The pupal stage (Fig. 15, Plate I) is spent in an oval cell in the soil. 
The figure represents the pupa on the beetle shown in Figure 16, Plate I. 

The Beetle 

The beetles of this group are characterized by the freely moving joint 
between the thorax and abdomen and by their power to spring into the 
air when placed on their backs. 

Our most common species 5 (Fig. 16, Plate I) is dark brown. Figure 
17, Plate I, represents a smaller, lighter colored species. The drawing 
to the right of the colored figure is the natural size of this beetle. 

LIFE HISTORY 

The life history of the soil-inhabiting species of wireworms is very 
similar to that of the white grubs. The eggs are laid in the soil. 
Usually meadows, pastures or other grass covered lands are selected by 
the females as places to deposit their eggs. 

Two or three years are required for the worms to reach maturity. 
Feeding takes place each season. When mature the worm forms an oval 
cell in the soil in which the change to the pupal stage takes place. This 
change occurs during the summer months. In the course of a few weeks 
the adult beetle emerges from the pupa. 

Most of the newly transformed beetles remain in the soil until the 
following season. However, a few leave their pupal cells soon after 
emerging. During the following winter these beetles hibernate under 
dead leaves, crop refuse or other material which furnishes suitable pro- 
tection against the cold and moisture. 

NATURAL ENEMIES 
Ground Beetles 

Wireworms are unusually free from attack by parasitic insects, but 
the predacious ground beetles destroy many of them. Several species 
of the Genus Calosoma, one of which is represented in Figure 2, Plate 
IX, Page 27, and their larvae, feed freely on this pest. 

Birds 

Many species of birds are very effective in destroying the beetles. 
The ill-famed crow is a noted wireworm destroyer. The food of the 
California shrike, or butcher-bird as it is sometimes called, is known to 
consist largely of adult wireworms during certain seasons of the year and 
where these are abundant. From 90% to 95% of the food eaten is 
composed of these beetles at such times, according to observations 
recorded by John E. Graf, in Bulletin No. 123, Bureau of Entomology, 
U. S. Department of Agriculture. 

Skunks 

Skunks, which are so effective in the destruction of white grubs, 
devour large numbers of wireworms as well as the adult beetles. In 
1914 the writer examined a quantity of excrement of the little, spotted 
skunk. No evidence of any other animal food aside from insects was 
found. Over 10% of the insects eaten were wireworms and click-beetles. 

( 6 ) See explanation of "Reference Figures." page 2 

54 



Sugar Beet Root-louse 

B. SUCKING ROOT FEEDERS 

I. SUGAR BEET ROOT-LOUSE 

(Figs. 1 to 9, 11 to 13, 16 to 18, Plate II, Page 13) 

Because of its universal distribution in the sugar beet growing sections 
of the West and the difficulty of controlling it, the sugar beet root-louse 
presents one of the most serious insect pest problems with which the 
beet growers and factory people have to contend. 

NATURE OF INJURY 

Visible effects of root-louse injury on the above-ground parts of the 
sugar beet do not appear until the number of lice becomes very great. 
At such times the color of the beet leaves changes from a dark to a yel- 
lowish green. This change in color alone must not, however, be taken 
as proof that a crop is being greatly damaged by root-lice. Sugar beets, 
especially when grown on light soil or watered too heavily, will turn 
light in color in the latter part of the season when not infested with root- 
lice. When the lice become very numerous the beet leaves wilt as though 
the crop were suffering from lack of water. Often the beets become so 
shrunken as to be loose in the ground and very much wrinkled. Such 
beets are very limber and can be bent almost double without breaking. 

The above is descriptive of exceptional cases. Whether effects are 
visible or not, if lice are present, on the surface of the roots and in the 
soil surrounding them will be found a whitish, mold-like substance. 
Intermingled with this and covered by it will be seen many small, wingless 
lice of a yellowish white color (Fig. 9, Plate II, Page 13), and if the season 
is well advanced some darker winged lice (Fig. 7, Plate II, Page 13) as 
well. 

The effect of lice on live stock is so well known that no one expects 
a lousy animal to make normal growth or put on fat. The loss of blood 
and possibly the irritation caused by the feeding of the lice stunt it and 
produce a very scrubby and inferior animal. The effect of lice on a sugar 
beet may be compared with that of lice on livestock. The lice take up 
the sap of the beet and the feeding irritates it. The combined effect of 
these two things is a small, stunted beet and one low in sugar content. 
Of course quite satisfactory yields and sugar contents are possible even 
though the beets are lousy. Nevertheless, nothing is more certain than 
that had they not been lousy both would have been higher. 

Carefully conducted tests show that infested beets contain from f % 
to 1% less sugar than uninfested beets in the same field. Also, the purity 
of juice of such beets is from 1% to 2% lower than uninfested beets. 
The average infestation reduces the yield by more than 1 ton per acre. 
In very severe cases the beets are killed or made worthless for factory 
purposes. 

METHODS OF CONTROL 

There is no known means of entirely preventing sugar beet root- 
louse losses. However, if the crop is properly handled they can be 
greatly reduced. 

55 



Sugar Beet Root-louse 
Irrigation 

It has been shown by Mr. J. R. Parker of the Montana Experiment 
station*, that the sugar beet root-louse does not multiply so rapidly in 
moist as in dry soil. Experiments conducted by him on The Great 
Western Sugar Company's farm at Edgar, Montana, and on the Gov- 
ernment Reclamation Project at Huntley, Montana, show that fields 
irrigated during the migration of the lice from the cotton-wood 
trees to the beet fields are much freer from root-lice at harvest 
than fields not irrigated until later. 

Migration begins about the 10th of June and is at its height about 
the 20th of the month in the latitude of Denver, Colorado. In the lati- 
tude of Billings, Montana, the height of migration is probably reached 
six to eight days later. Since the losses due to this insect are propor- 
tional to the number of lice present and feeding on the crop, anything 
which reduces their number reduces the loss as well. Frequent irriga- 
tions during the growing season reduce the infestation and also increase 
the yield of beets. 

In a leaflet issued by Mr. Parker and circulated by The Great West- 
ern Sugar Company at Billings, Montana, the results of several years' 
work in the control of the sugar beet root-louse, show that there are 56.2, 
46.6 and 25.6 beets out of every 100 infested where two, three and five 
irrigations respectively were applied. 

The sugar content was 15.8%, 17.1% and 17.2% for two, three and 
five irrigations respectively. 

The gross returns per acre were $82.27 for two, $85.61 for three, and 
$96.07 for five irrigations. 

To some, early irrigation may seem like "jumping from the frying 
pan into the fire, " since it is quite generally believed that early watering 
is detrimental to sugar beets. Quite to the contrary it has been found 
that irrigating as early as June 22nd produces better results in yield and 
per cent of sugar in the majority of years. It is a fortunate coincidence 
that early irrigation gives best results in just the years which are favor- 
able for the development of root-lice; i. e., years when the winter and 
early summer are dry. 

Through experiments conducted on The Great Western Sugar Com- 
pany's Experimental Farm at Longmont, Colorado, it has been found 
that, as an average of six years tests, irrigating as early as June 22nd to 
25th has produced a yield of 14.66 tons per acre and 16.05% sugar, while 
beets irrigated the first time July 5th to 10th gave a yield of but 14.23 
tons per acre and a sugar content of 15.84%. Both the early and late 
irrigated beets were watered three times each season. The gross re- 
turns were $87.29 per acre for the early and $83.80 for the late 
irrigated beets, without any greater expenditure of labor or water 
for the increased returns due to early irrigating. 

Fall and Spring Irrigation; Plowing 

Fall or early spring irrigation will no doubt destroy most of the lice 
in the soil. However, if the destruction of the lice is the only reason 



*"Life History of the Sugar-beet Root-louse, Pemphigus betae," Journal of Economic Entomology. 
Vol. 7. No. 1 (1914). 

56 



Sugar Beet Root-louse 

for this irrigation it is doubtful if the results will warrant the use of the 
water. During the process of plowing and working down the seed bed, 
the majority of the hibernating lice are destroyed. 

Rotation 

While quite a number of lice live over from season to season in the 
soil of old beet fields, yet they are of little importance as compared with 
the lice from the narrow-leaf cottonwood trees as a source of infesta- 
tion. For this reason rotation is of very little avail in preventing 
losses. The results of a survey covering 80,000 acres, made in 1916, 
showed that 83 beets out of 100 were infested with root-lice where sugar 
beets were grown on old beet ground and 82 out of 1 00 where they fol- 
lowed all other crops. This proves conclusively that rotation will not 
prevent root-louse losses. The presence of lice in the soil in the spring 
is no reason why such fields should not be planted to beets provided 
they are otherwise fit. 

The results of the survey mentioned above show quite conclusively 
that the destruction of all narrow-leaf cottonwood trees within the beet 
growing sections will reduce the damage done by the sugar beet root- 
louse. Therefore, the cutting of these trees is strongly to be recom- 
mended. However, it will not entirely free beet fields of this pest, since 
many lice reach them from the foothills and canyons. 

DESCRIPTION AND LIFE HISTORY 

Mention has already been made of winged lice on the beet roots in 
the fall. During warm, sunny autumn days swarms of these little 
winged lice leave the beet fields and fly to the narrow-leaf cottonwood 
trees. 

About every narrow-leaf cottonwood with the rays of the sun 
glistening on their wings, thousands of lice sway in and out among the 
branches. One by one they alight to go hurrying up and down as if 
fearful lest the oncoming winter overtake them before suitable homes 
for their young have been found. 

In deep crevices and under loose pieces of bark these winged migrants 
from the beet fields deposit their minute, yellowish young. These are 
of two kinds, tiny little females (Fig. 18, Plate II, Page 13), and still 
smaller males (Fig. 16, Plate II). (Note the minute representation of 
the actual size of these lice, shown at the left of the figures.) Almost 
microscopic in size, mouthless and living but a few days, their sole object 
in life is to produce the solitary egg which each female lays. This accom- 
plished the female dies, the male having died shortly after mating took 
place. 

Figure 13, Plate II, Page 13, is the antenna of Figure 16, Plate II, 
Page 13, greatly enlarged. 

The eggs, one of which is shown very much enlarged (Fig. 17, Plate 
II), are about ^ ? .of an inch long and one-fourth as broad. Snugly 
tucked away in some crevice of the bark they remain until the warm 
days of spring cause the buds to swell, when from each egg a small, dark 
louse (Fig. 2, Plate II, much enlarged) emerges. As soon as hatched 
this little louse starts in search of an opening bud. When one is found 

57 



Sugar Beet Root-louse 

it crawls in among the expanding leaves and begins to feed upon the 
upper surface of one close to the midrib. This feeding causes a depression 
to form and the leaf to turn light in color (Fig. 1-A, Plate II). 

In the course of a few days this depression has become a swelling on 
the under side of the leaf (Fig. 4, Plate II), which is now entirely closed 
on the upper side (Fig. 3, Plate II). In this gall, as the swelling is called, 
the little louse is securely protected from inclement weather and the 
sharp-eyed birds as they flit among the branches. Both the gall and the 
louse increase in size for some time, until the former appears as in Figure 
5, Plate II, and the louse, which is called a stem-mother, as shown in 
Figure 6, Plate II. 

This rotund stem-mother gives birth to several living young daily 
during the next month or six weeks. If opened about the middle of 
June the gall will be found to contain many pale lice all surrounded by 
a whitish substance. This waxy material is secreted by glands and 
escapes through what are called wax-pores, which are arranged in rows 
across the body of the insect. These appear as light, round spots on the 
back. (Fig. 6, Plate II). 

The young of the stem-mother do not resemble her in form, being 
slender of body and at first wingless. As they grow older wing pads 
appear on their shoulders. After shedding their skins several times, 
growing darker with every succeeding molt, the last larval skin is shed 
and a delicately winged louse (Fig. 7, Plate II) emerges. The antenna 
of this winged louse is shown in Figure 8, Plate II. 

About the time the first winged lice appear the mouth of the gall 
begins to open. Through this opening the winged lice escape and fly 
or are blown by the wind far and wide among the beet fields, where they 
settle on the beets and deposit their young, which immediately descend 
to the ground and take up their abode on the beet roots. All the young 
of the winged migrants from the Cottonwood trees are wingless and when 
full grown appear as shown in Figure 9, Plate II. 

The antenna of the wingless lice which are found on the beet roots 
is shown in Figures 11 and 12, Plate II. 

These wingless lice give birth to still more wingless lice. This goes 
on until several generations and hundreds of lice have been produced on 
the beets. Then with the return of fall some of the lice on the beet roots 
develop wing pads like those of the young of the stem-mother in the gall. 
After acquiring wings these lice are known as the fall migrants. 

These migrants return to the narrow-leaf cottonwoods and there 
deposit their young. Thus we have followed the lice from the galls on 
the cottonwood trees to the beet fields and back again to the cottonwoods. 

■ Not all of the lice become winged in the fall, however. Some wing- 
less ones remain over the winter in the soil, where they hibernate in 
earth-worm burrows and other openings. Thus we see that nature has 
provided two means of carrying the beet root-lice over the winter: the 
hibernating lice in the soil, and the eggs in the crevices of the cotton- 
wood bark. 

58 



Sugar Beet Root-louse Sugar Beet Nematode 

NATURAL ENEMIES 

While in the galls a bug* (Fig. 14, Plate II, Page 13) preys upon 
the lice. In the beet fields the little lady-beetle 1 1 and its larva (Figs. 
10 and 15, Plate II, Page 13) feed upon the root-lice. This larva, 
which is not very much larger than a good sized louse, secretes a white, 
waxy substance with which its body is covered, making it resemble to 
a remarkable degree one of the lice upon which it feeds. The pupa of 
this beetle (Fig. 14, Plate VII, Page 23) is surrounded by the cast larval 
skin and white flocculent coating. 

The larvae or maggots of the Syrphus-fly 14 (Fig. 13, Plate VI, Page 
21) do their part in destroying this pest. 

Every season large numbers of the lice are killed by a fungous dis- 
ease.** This fungus develops within the lice and finally causes their 
death. Were it not for these natural checks the damage caused an- 
nually by the beet root-louse would be far greater than it is now. 

Slender, yellowish-white maggots are often seen among the lice on 
beet roots. These are the larvae of a small, striped fly| (Fig. 14, Plate 
VI, Page 21). Recent investigations f show that these maggots are 
very effective in destroying the beet root-lice. During the latter part 
of the season small, oval, brown bodies will be seen among the lice also. 
These have often been mistaken for the eggs from which the lice hatch. 
Instead of being root-louse eggs they are the thickened larval skins 
within which the maggots change into the flies mentioned above. 



2. SUGAR BEET NEMATODE 

(Figs. 8, 9 and 10, Plate III, Page 15) 

Quite early in the history of the beet sugar industry in Europe it 
was noticed that the yield of sugar beets was steadily dropping off in 
certain districts. In spite of the efforts of the growers to maintain the 
yield by using fertilizers, and in spite of their increasing knowledge of 
the handling of the crop, the tonnage secured was so unsatisfactory that 
the growing of sugar beets was discontinued on many fields. 

Many theories were advanced in explanation of this condition. The 
most prevalent and generally accepted of these attributed the trouble 
to an exhaustion of the mineral plant foods of the soil. 

It was noticed that those fields where beets had been grown con- 
tinuously for several years were most affected. This led the Germans to 
give the name "Rubenmiidigkeit, " or "beet weariness, " to this malady. 

A German scientist named Kuhn was first to associate the soil in- 
habiting eelworm or nematode (Heterodera schachtii) with this trouble. 

The sugar beet nematode so far has been found only in a few well 
defined localities within the territory in which The Great Western Sugar 
Company operates. 

*Authocoris melanocerus. 
**Empusa aphidis. 
tChloropisca glabra. 

tJ- R Parker. "Life History and Habits of Chloropisca glabra Meign.." Journal of Economic Ento- 
mology. Vol. XI. No. 4 (1918). 
(li-n) See explanation of "Reference Figures," page 2. 

59 



Sugar Beet Nematode 




Fig. 6. A Sugar Beet infested with Sugar Beet Nematodes. The white bodies, of 
the female nematodes can be seen clinging to the rootlets. 




Fig. 7. A Sugar Beet affected with Curly-top, showijg the characteristic dense mass of rootlets. (After C. 0. 
Townsend, Fanners' Bulletin No. 122, U. S. Department of Agriculture.) 



Sugar Beet Nematode 

NATURE OF INJURY 

The young sugar beet nematodes search out a beet root, and by 
piercing it with their strong spear-like mouth parts, embed themselves 
within the tissue. They then begin to feed upon the juices of the beet. 

Effect on Roots 

The presence of the nematodes causes an irritation of the roots. 
Because of this irritation, and because the sap is consumed by the nema- 
todes, the roots are unable to carry the water and plant food to the beet, 
and the growth of the plant is interferred with. 

In an attempt to overcome this trouble the beets send out many 
new rootlets from the root seams at each side of the main root. In 
Europe these beets have been called "bearded roots" or "hunger roots. " 
Such beets (Fig. 6, Page 60) resemble the "whiskered beets" suffering 
from a severe attack of the disease known as "Curly-top" (Fig. 7, Page 
60). 

If carefully removed from the soil, the rootlets of infested beets 
will have many minute, pearly-white bodies clinging to them (Fig. 9, 
Plate III, Page 15). These are the mature female nematodes. 

In extreme cases the weakened roots become infested with fungi and 
bacteria which cause them to rot or the plants die because of lack of 
nourishment. 

Effect on Leaves 

The presence of nematodes becomes apparent in the appearance of 
the leaves as the season advances. The foliage of the infested plants 
turns light in color, becoming a yellowish green, or they have the dull, 
gray-green color of beets suffering from lack of water. The leaves wilt 
and finally lie flat on the ground, failing to recover during the night. 
The outer ones finally die. The growth of the inner leaves is seriously 
interfered with, and in severe cases they die also. If the beet does not 
succumb to the attack, the new leaves produced fail to attain normal 
size and are often much curled and distorted. Late in the season, beets 
which have survived the attack are often a darker green than their 
uninfested neighbors. 

Effect on Sugar Content 

Not only is the size of the roots and leaves of the beets affected 
but the sugar content is greatly reduced as a result of the nematode 
attack. For example, moderately infested beets contained 11.35% 
sugar and badly infested ones only 8.4% in a field where healthy plants 
had a sugar content of 14.9%.* 

HOW NEMATODES SPREAD 
By Their Own Movements 

Sugar beet nematodes have the power of increasing by their own 
movements the area infested. In certain stages of their development 
and under favorable conditions they can travel considerable distances 
in the soil. The ravages of this pest have been known to be extended 
from 50 to 75 feet each season in this way.* 

'Harry B. Shaw. "Control of the Sugar-Beet Nematode," Farmers" Bulletin No. 772, U. S. Depart- 
ment of Agriculture (1916). 

61 



Sugar Beet Nematode 
Carried by Irrigation Water 

Irrigation water passing over infested areas carries many nematodes 
to uninfested localities with the soil washed away from these areas. 

The use of factory waste water for irrigation purposes has resulted 
in spreading this pest over large areas in those localities where the nem- 
atodes exist. 

Carried by Implements, People and Live Stock 

Nematode infested soil is often carried from infested to uninfested 
fields on the farm implements used in their cultivation. 

The wagons used in hauling a crop from infested fields or in hauling 
manure onto such fields often carry the nematodes to other fields. 

Work animals or stock allowed to run on infested land, as well as 
people, spread this pest by carrying the eelworm in the soil clinging to 
their feet. 

In Manure of Animals 

The sugar beet nematode does not pass through the digestive organs 
of sheep alive. There seems to be no evidence that this is true of other 
farm animals. It is therefore quite possible that nematodes may be 
carried in the manure of other animals, and if beet tops on infested land 
are to be pastured, sheep should be used for this purpose. 

METHODS OF CONTROL 

The fact that the sugar beet nematode is a really formidable 
pest, if allowed to spread, cannot be too strongly impressed upon 
the minds of all beet growers, especially as it occurs in damaging 
numbers in several beet growing sections of the United States, 
including a small area in Colorado. 

Since there are no known methods of entirely freeing the soil of 
nematodes which can be used in field practice, the adoption of proper 
precautions to prevent their introduction into new fields is of the greatest 
importance. Once this eelworm is established, the prevention of its 
spread is no less important than the establishing of a system of crop 
rotation which will check its multiplication. 

How to Prevent Spread of Nematodes 

(1) No waste water should be allowed to run from infested to un- 
infested fields. 

(2) In infested areas, factory waste water should not be used for 
irrigation purposes unless first properly treated with lime. 

(3) All implements used in working infested land should be very 
carefully cleaned by removing all soil from them before they are used in 
uninfested fields. This includes the cleaning of wagon wheels. 

(4) The feet of persons and work animals should be thoroughly 
cleaned before going from infested to uninfested fields. 

(5) Live stock should not be allowed to run on infested land unless 
it is to be confined there until removed to market. 

(6) Beet tops from infested land should not be removed but should 
be pastured on the land where grown. 

(7) The manure of animals fed on beet tops from infested land 
should not be used on uninfested land. 

62 



Sugar Beet Nematode 



How to Check Multiplication of Nematodes 

Field Surveys 

All suspected fields should be thoroughly examined, so that the 
exact location and extent of infested areas may be known. That such 
surveys of suspected lands be made is of the greatest importance. 

Local Treatment 

If the infested areas are small, local treatment may be all that is 
necessary. All plants on the area should be pulled, together with those 
from a strip several feet wide all around it. These should be destroyed 
by burning on the spot. 

A trench about one foot deep and one foot wide should then be dug 
around the infested spot and this filled with quick-lime. The surface 
of the infested area should be covered with lime an inch or two deep and 
this thoroughly mixed with the soil. Frequent mixing of the limed soil 
will add to the effectiveness of the treatment. 

Pasturing with Sheep 

Pasture the beet tops grown on infested land to sheep, rather than to 
other stock, as the nematode in the tops eaten will thus be destroyed, and 
will not be returned to the soil through the manure. 

Rotation 

The sugar beet nematode infests the roots of many weeds and cul- 
tivated crops. The following list of plants known to be subject to attack 
is taken from Farmers' Bulletin No. 772 of the U. S. Department of 
Agriculture. 



Alfalfa 

Allseed 

Barley 

Beans, Dwarf Pea 

Beans, Lima 

Beets, Garden 

Beets, Sugar 

Cabbage 

Cabbage, Chinese 

Cauliflower 

Celery 

Clover, Crimson 

Clover, White 

Corn 

Cress 



Dandelions Pinks 

Foxtail, Green Potatoes 

Hemp Radishes 

Hops Rape 

Kale Rutabaga 

Kohl-rabi Rye 

Lentils Sorghum 

Lupine, Yellow Spinach 

Meadow-grass, Annual Sunflower 
Meadow Oat-grass, Tall Timothy 

Mustard Turnips 

Oats Vetch 

Parsnips Wheat 
Peas, Garden 
Peas, Sweet 



In the above mentioned bulletin the author lists the following crops 
as being available for Colorado and neighboring states for rotation on 
infested land: 

Cow Peas Asparagus 

Soy Beans Lettuce 

Sweet Clover Cantaloupe 

Rye Barley 

The Millets Wheat 

Tomatoes Cucumbers 

Potatoes 
Potatoes are often slightly injured. 

63 



Sugar Beet Nematode Root-knot Nematode or Gallworm 

DESCRIPTION AND LIFE HISTORY 

In the course of its development the sugar beet nematode passes 
through four forms or stages : the egg, two larval stages, and the adult. 

The Egg 

Each adult female produces from 300 to 400 eggs. These are color- 
less and broadly oval or kidney-shaped. They are extremely small, 
being only about ^o °f an i ncri long. 

The Larval Stages 

The young nematodes, or larvae, are very active, threadlike creatures. 
Being colorless and almost microscopic in size, they are seldom noticed 
in the field. 

It is in the first larval stage that the nematodes enter the tissue of 
the beet roots. The first larval skin is cast shortly after entering the 
beet and the larva takes on a more robust form. 

The Adult 

With a second molt the nematode becomes an adult male (Fig. 10, 
Plate III, Page 15), or female (Fig. 8, Plate III, Page 15). 

The Brown-cyst Stage 

As cold weather approaches' or conditions become unfavorable for 
the development of the females, certain individuals pass into a resting or 
preservation stage which is known as the brown-cyst stage. 

In the cyst form the female passes the winter or the period of un- 
favorable conditions protecting the eggs until conditions become favor- 
able for further development. With the change of conditions the eggs 
begin to hatch. They do not all hatch at once, however, but may con- 
tinue to do so ror long periods that may extend over several years. 

3. ROOT- KNOT NEMATODE OR GALLWORM 

This nematode, which is very closely related to the sugar beet nem- 
atode, seriously interferes with the growing of sugar beets in some 

localities. 

This nematode has been 
found in the Sterling, Brush, 
Ft. Morgan and Scottsbluff 
districts. 

NATURE OF INJURY 

The roots of infested plants 
present a very characteristic 
appearance. The presence of 
the females and larvae in a 
root is indicated by irregular 
swellings (Fig. 8, Page 64), 

Fig-. 8. Small Sugar Beets infested with the , , , .. .. . 

Root-knot Nematode. The bead-like swellings Caused by tne irritation Set 
on the small roots and the enlargements of the , tVipcp pp1wr>rm<; 

main root are caused by the nematodes. up Dy tnese eeiWOIIIlS. 

64 




Root-knot Nematode or Gallworm 

METHODS OF CONTROL 
Prevent Spread of Nematodes 

In order to prevent the spread of this pest, the same precautions 
should be observed as in the case of the sugar beet nematode (See page 62) . 

Potatoes grown on infested land should not be used for seed, as the 
nematodes pass the winter within the tubers. 

Such plants as tomatoes, cabbage, strawberries, kale, sweet potatoes, 
asparagus and horse-radish should not be taken from infested soil and 
transplanted in nematode free fields. 

Nematode Eradication 

There is no practical means of entirely eradicating the gallworm in 
large fields. In the case of hotbeds and greenhouses soil fumigants can 
be used, but these are too expensive for field use. 

Rotation 

The most practical method of reducing the numbers of nematodes 
is to rotate with such crops as are not attacked. Mr. C. S. Scofield* 
gives the following list of crops as suited for planting on infested soil : 

Barley Sorghum 

Oats Milo 

Wheat Kafir 

Rye Timothy 

Corn Red Top 

The value of growing the resistant crops named above is strikingly 
illustrated by the results of a survey of five large areas in which all sugar 
beet fields infested with the root-knot nematode were located and a record 
secured of the crop grown on all fields, both infested and uninfested the 
year previous. It was found as the per cent of resistant crops grown 
increased, the per cent of infested beet fields decreased. These figures 
are given in the following table: 









% of total 




Total fields 


% of total 


growing nematode 


Area 


examined 


infested 


resistant crops 


A 


366 


58.47 


5.19 


B 


480 


51.87 


6.66 


C 


768 


28.77 


9.77 


D 


671 


2.08 


12.09 


E 


676 


1.03 


28.06 



LIFE HISTORY 

During the greater part of their lives these worms remain embedded 
within the tissue of the roots of their host plants. 

Upon reaching maturity the fertilized females begin the production 
of eggs. Some of these hatch within the body of the parent, the young 
ultimately escaping into the surrounding tissue of the host plant. Others 
are laid at the rate of ten or fifteen daily.* 

*"The Nematode Gallworm on Potatoes and Other Crop Plants in Nevada," Circular No. 91, Bureau 
of Plant Industry, U. S. Department of Agriculture (1912). 

65 



Root-knot Nematode or Gallworm 

Shortly after the larvae hatch they escape from the root of the host 
plant and spend a time in the soil. Soon they search out the root of a 
suitable plant and burrow into it, where they feed upon its sap, causing 
the characteristic swellings already mentioned. 

The nematode gallworm lives from season to season embedded in 
the tissue of the host plant either in the egg or larval stage. The life of 
the adult is only a few weeks under favorable conditions. 

Plants and crops subject to severe infestation which should never 
be planted on infested land :* 



Beet 


Pumpkin 


Cowpea 


Carrot 


Potato 


Rape 


Celery 


Salsify 


Soy bean 


Cucumber 


Squash 


Catalpa 


Egg plant 


Tomato 


Cherry 


Lettuce 


Watermelon 


Elm 


Muskmelon 


Clover 


Peach 



Plants subject to attack but not seriously injured by nematode 
gallworms: These should not be planted on infested land as they will 
serve to keep the worms alive.* 



Alfalfa 
Vetch 

Sweet clover 
Asparagus 
Cabbage 


Cauliflower 
Garden pea 
Horseradish 
Strawberry 
Lima bean 


Kale 
Onion 
Radish 
Spinach 
Sweet potato 


Crops suited for planting on infested land:* 


Barley 
Oats 
Wheat 
Rye 


Corn 

Sorghum 

Milo 


Kafir 
Timothy 
Red top 



*C. S. Scofield. "The Nematode Gallworm on Potatoes and Other Crop Plants in Nevada," Circular 
No. 91, Bureau of Plant Industry. U. S. Department of Agriculture (1912). 



66 



Leaf-eating Caterpillars Sugar Beet Webworm 

CHAPTER III 



LEAF FEEDERS 

Either because they feed exposed to the view of the most casual 
observer or because their work is such as to attract general attention, 
the leaf-feeding insects are much more universally known to the layman 
than the root-feeding insects. In a general way the methods of controlling 
this class of insects are common knowledge also. However, this knowl- 
edge is of a superficial nature; that is, it is general instead of specific. 
This lack of knowledge of the particular insect involved has led to much 
waste of money, energy and material, either because the wrong remedy 
has been applied or the right one was not applied in the correct way or 
at the right time. 

A. BITING LEAF FEEDERS 

(Caterpillars, Beetles, Grasshoppers, Crickets, Leaf-miners) 

1. LEAF-EATING CATERPILLARS 

The young of moths or millers and butterflies are known by the 
general name of caterpillars. In size, shape, color and body covering 
they differ greatly in different species. 

Some are but a fraction of an inch in length, while others attain a 
length of six or seven inches. For the most part caterpillars are cylindri- 
cal, being several times as long as thick. Some are grub-like in form and 
others resemble dead leaves or twigs in shape and color. The bodies of 
many are bare, those of others are covered with long hairs. In some 
species these hairs are connected with poison glands. If these cater- 
pillars come in contact with the bare hands or face the sensation is very 
similar to that caused by the sting of nettles, only more severe. Some 
caterpillars are really formidable in appearance because their bodies are 
covered with large spines or spine covered tubercles. 

In the kinds of food eaten, caterpillars are as variable as in shape, 
size or color. Some bore in the wood of trees, others feed upon hair, 
wool, horn and like substances. A few feed upon scale insects and the 
larvae of borers. Several species attack growing fruits, while others 
destroy stored fruits and grains. The species with which we are most 
concerned, and which are discussed in the following pages, feed upon the 
leaves of plants. Among this class are to be found some of the worst 
enemies of cultivated crops. 

(a) SUGAR BEET WEBWORM 

(Figs. 3, 4, 5, 6, 8, 9, 10, 11, Plate V, Page 19) 

The sugar beet webworm is one of the most destructive leaf-eating 
insects attacking the sugar beet. Like many of our most injurious insect 
pests, it was introduced into this country from the Eastern Hemisphere, 
appearing first on the Pacific coast. In 1869 it damaged beets in Utah. 

67 



Sugar Beet Webworm 

Since that time it has spread over the entire sugar beet growing areas of 
the country. 

The worst outbreaks of webworms which have occurred in the ter- 
ritories in which The Great Western Sugar Company is operating took 
place in 1918 and 1919. During the season of 1918, the June and August 
broods both caused great damage. Some fields were injured by both 
broods. 

An accurate statement of the acres damaged in 1918 and the degree 
of damage was reported by the fieldmen of The Great Western Sugar 
Company. These reports show that 31,000 acres were injured. The 
first brood injured 5,500 acres and the second 25,500 acres. Over 7,000 
acres were damaged to the extent of two tons per acre, over 7,000 acres 
to the extent of one ton per acre and nearly 15,000 acres to the extent of 
\ ton per acre. The total loss to the growers and the industry was not 
less than 26,450 tons of beets. These at $10.00 per ton, the price in 1918, 
represents a money loss of $264,500. Over 16,000 acres were sprayed 
with Paris green at the average rate of 4 pounds per acre, and much loss 
thus prevented. This required 84,000 pounds of Paris green, much of 
which was furnished the growers at a reduced cost per pound by The Great 
Western Sugar Company. 

This loss could have been very much more reduced if all growers had 
realized in time that there was danger and had had themselves properly 
prepared. Too late spraying was responsible for much of the loss. 

As this bulletin goes to press the campaign against the first brood 
of 1919 is drawing to a close. This brood, which is the largest known in 
the history of sugar beet growing in the United States, covered practically 
all beet growing areas in Colorado, Nebraska, Montana and Wyoming. 

In order to assist the growers in combating it The Great Western 
Sugar Company purchased several hundred traction sprayers and dis- 
tributed about 700,000 pounds of Paris green in its territories. Had it 
not been for this assistance the loss to the growers would have far exceeded 
that caused by both broods of 1918. 

NATURE OF INJURY 

Webworms injure sugar beets by destroying the leaves. This re- 
tards the growth, thus reducing the yield and sugar content. All other 
things being equal, the loss is quite proportional to the loss in leaves. 
The greater the amount of leaf surface destroyed, the greater the loss. 
On the other hand, the losses depend somewhat upon the time of season 
when the damage is done, also upon the weather condition immediately 
after it is done. 

Small beets may be killed outright if the leaf surface is so small that 
the worms attack the crowns. Larger beets may have their leaves 
entirely eaten off but recover by putting out new leaves. (See Fig. 9, 
Page 69, and Fig. 10, Page 70.) 

The first indications that a crop may be injured by the sugar beet 
webworm is the appearance of the moths (Fig. 11, Plate V, Page 19) in 
the field. These moths are active and easily disturbed during the day. 
When present they will be noticed flying ahead of the cultivator or of 
one walking through the field. Their flights are short and jerky and they 
usually alight on the under side of a leaf or on the ground. Catch one 

68 



Sugar Beet Webworm 

of the moths and compare it with the figure. If it is the same then look 
for the eggs, continuing to do so for several days. Call the attention 
of the Sugar Company's fieldman to the moths and get his advice. 

The eggs will be found on the under side of the beet leaves, on lamb's- 
quarters or on Russian thistle if these weeds are growing in the field. Of 
a pearly-white color and about the size of a small pin-head, they are not 
easily seen unless careful search is made for them. 




l^ftSi" 




i -.-tff- 



Fig. 



Sugar Beet badly damaged by Webworms 



Even though no eggs can be found, do not assume that all danger is 
past. Often the eggs are overlooked and the first indication you have 
that your crop is infested is the presence of newly hatched worms hang- 
ing from the under side of the leaves by a short web. These can best 
be seen by getting down near the'ground and looking up and down the 
rows. Both the worms and web are light colored and not very easily 
seen unless the light is just right. Looking away from the sun makes 
them more easily discerned. 

Picking leaves at random over a field and noting the number of eggs 
or young worms present is a very good way of estimating the possibility 
of damage in the near future. Great care must be taken not to under- 
estimate this possibility, however. One or two worms or eggs on 
one-half to three-fourths of the leaves indicate the presence of enough 
worms seriously to injure the crop later. As some of the worms drop 
from the leaves when they are broken off, the worms seen do not represent 
all present. 



69 



Sugar Beet Webworm 



Very often a few eggs in one part of a field indicate that in some 
other portion there are many more. Not infrequently the moths lay eggs 
by the hundreds and thousands over a very small area. This is quite 
as apt to be in the center of the field, or at least some distance from the 
border, as near the edge of the field. All weedy spots should be carefully 
examined and the weeds removed as soon as possible, as these are often 
the places where the injury starts and spreads to the entire field. 

It is hard for a person who has not seen a severe outbreak of web- 
worms to realize that what appears to be but a few small worms is capable 
of causing the loss of several dollars worth of beets. This fact has been 
the cause of a great deal of the loss in the past. 

If eggs or young worms are found it is time to get your spray 
machine out, or your neighbor's if you do not have one of your 
own, and provide a supply of Paris green ready to apply as soon as 
the eggs begin to hatch. 

As the young 
worms feed entirely 
on the under side 
of the leaves for 
several days after 
they leave the eggs 
and do not eat away 
the upper surface, 
their presence is not 
suspected, many 
times, until they 
are so far developed 
that much damage 
is done before they 
can be controlled. 

When first 
hatched the worms 
are so small that 
their capacity for 
doing damage is 
limited. As they 
increase insize their 
appetites become 
almost insatiable. The rapidity with which they will completely strip a 
beet field of leaves is almost beyond belief. Each worm will eat several 
times its own weight of beet leaf every day. So rapid is their work that 
although there is no apparent injury today, tomorrow or the next day 
large spots in the field may be completely defoliated. 

These spots very often occur in the center of the field, thus they are 
overlooked unless it happens that the grower is cultivating or irrigating 
at the time. 

70 




Fig. 10. Sugar Beets badly damaged by Webworms 



Sugar Beet Webworm 

Careful watch should be kept of the beets during the last half 
of June and the latter part of July and early August. Examine 
the under side of the beet leaves every day or so. 

If young worms are present small pits will be eaten into the lower 
surface of the leaves. In case such pits occur the little whitish-yellow 
worms should be found not far away. If the worms are several days old 
they will be greenish in color, appearing more like the full grown worm 
(Fig. 6, Plate V, Page 19). At this age they will be found on both sides 
of the leaves. The edges of the leaves will be eaten away, leaving them 
ragged, or the entire leaf will be eaten with the exception of the heavy 
veins. The young leaves at the heart of the beet are usually the last 
eaten. 




Fig. 11. Field of Sugar Beets showing "Work of the Sugar Beet Webworm. Bare 
areas were weedy when eggs were laid. Balance of field was free from weeds. 

Sometimes the worms will be concealed in webs spun over the leaf, 
usually near its base. In case small, roundish, dark colored pellets 
are seen on the leaves, a webworm or some other leaf-eating caterpillar 
is present. The culprit should be located and his identity established. 

METHODS OF CONTROL 
Destruction of Weeds 

The sugar beet webworm moth shows a particular liking for lamb's- 
quarters and Russian thistle as plants on which to deposit its eggs. For 
this reason if these weeds are abundant in a field of beets the crop is apt 
to be damaged by webworms if the moths are at all numerous in the 
vicinity. Volunteer alfalfa is also a menace to the crop. 

The effect of allowing weeds to grow in a crop of beets is strikingly 
illustrated by the cut on page 71 (Fig. 11). 

71 



Sugar Beet Webworm 

At blocking and thinning time this field was quite free of weeds 
except a strip running entirely across the picture from right to left 
and indicated by the bare spots at either side. The hand labor began 
thinning before the webworms appeared, cleaning out the rows, including 
the center portion of the weedy strip, but leaving the weeds in the sec- 
tions at each end represented by the bare spots. They then moved to 
another part of the field. In the meantime the webworm moths deposited 
thousands of eggs on the weeds left. 

When the labor returned to this part of the field both the weeds and 
the beets among them were stripped of their leaves. The beets on that 
part of the weedy strip that had been cleaned out earlier were not dam- 
aged. The worms were just moving to the beets surrounding the weedy 
patches, but a thorough application of Paris green applied according to 
the instructions given later killed them and no further damage was done. 

Furrow Trap 

Weedy ground bordering a beet field is very often as bad as weeds in 
the field. As soon as the worms have destroyed the weeds on which they 
hatch, hunger compels them to search for food. At such times they 
travel in armies, devouring whatever green thing comes in their way. 
A furrow plowed about the field and a small stream of water kept running 
in it will prevent the advancing worms from entering it. Newly cut 
alfalfa thoroughly sprayed with Paris green placed in the path of the 
oncoming army will destroy the worms by thousands. 

Irrigation 

In case both the moths and worms escape your observation and 
you are not aware that your crop is being damaged until a large por- 
tion of the leaves are eaten, the damage can sometimes be lessened by 
applying water to the crop, thus stimulating the growth of beets. This 
is especially true if the season is dry. 

Poison 

After the webworms have appeared in a field the only way to prevent 
loss is to kill them by spraying with some poison. Paris green seems 
best for this purpose. Being prepared for quick action as soon as 
the proper time conies to begin the fight is extremely important. 
Have all your forces mustered, all equipment in working order 
and a good supply of Paris green on hand. When the time 
comes strike and strike hard, working as rapidly as possible. 

The most vulnerable period of the webworm's life is during the first 
few days after it leaves the egg. There are two reasons why this is the 
best time to fight this enemy of the beet crop : 

(1) If killed when young the worms will not have time to do much 
damage, which means that they will not eat as much leaf before 
dying as they would if they were older. 

(2) It requires less poison to kill the young worms. 

However, do not think that because less poison is needed to 
kill the young worms that less should be used, for this is not the 
case. Too diluted a poison will mean an unnecessary consumption of 
leaves to bring about the death of the worms. 

12 



Sugar Beet Webworm 

Paris green gives more satisfactory results and works more quickly 
than any poison yet used for killing sugar beet webworms. 

In using this poison apply not less than 4 pounds per acre. 
(For the method of determining the amount of poison applied per acre, 
see "Test Your Sprayer" on page 35). 

A good type of traction sprayer, when properly adjusted, should 
apply about 50 gallons of water to the acre. If too little water is used 
the beet plants are apt to be burned ; if too much is used much poison 
is wasted. 

Arsenate of lead acts very much more slowly than Paris green, 
therefore seldom gives satisfactory results. This poison can be secured 
in two forms, dry and as a paste containing 50% water. These are not 
recommended except in case Paris green cannot be secured. When 
used, not less 
than 8 pounds 
of the dry or 16 
pounds of the 
paste should be 
applied per acre. 
If the worms are 
large, arsenate of 
lead is not recom- 
mended, as it acts 
too slowly. 

Best results are 
only secured 
when the poison 
is applied with a 
pressure sprayer 
which will main- 
tain a pressure of 
80 pounds. Such 
a machine pro- 
duces the fine 
mist-like spray 
which is necessary 
in order to place 
the poison on the 
under side of the 
leaves. 

The effect of spraying at the proper time, with the proper equipment 
and with the proper amount of Paris green, is clearly shown in Figure 
12, Page 73. The left of the cut shows the unsprayed portion of the 
field and the right the sprayed portion. 

See caution regarding the handling of Paris green, given on 
page 37. 

WHY GROWERS DO NOT SPRAY 

Beet growers have innumerable excuses for not spraying, few of 
which will stand the test. 




Fig. 12. 



Result of Spraying — Left, Unsprayed; 
Right, Sprayed 



73 



Sugar Beet Webworm 
Cost Too High 

The cost is one of the reasons most frequently given for not spraying. 
It costs not to exceed $3.00 an acre to apply Paris green with labor at 
$3.00 per day and Paris green at 50 cents per pound. One thorough 
spraying may save the grower $20.00 worth of beets. Even though a 
moderate amount of damage is done in spite of the spraying, a saving of 
one ton or $10.00 an acre can be made. 

Spraying Interferes with Haying 

Some growers will not spray because it is haying time when the 
worms appear. Two men and one team can handle at least 15 acres a 
day and should do 20 to 25 acres. If a grower has 25 acres he can spray 
it in one day and save one or two tons of beets per acre or $250.00 to 
$500.00 in a day by spending a day's time and $75.00 for labor and poison. 
This is not a bad interest on his investment. 

Fear of Poisoning Stock 

The fear of poisoning stock by feeding sprayed beet tops often keeps 
a grower from spraying. As sprayed beet tops have been fed for many 
years without killing stock, this excuse seems to have no foundation. 
The fact that only a portion of the leaves present when the spraying is 
done ever enter the feed lot, because they have died and fallen off, to- 
gether with the fact that the poison is very easily washed off by showers, 
would seem to reduce the question of poisoning stock to the very remotest 
of possibilities — so remote in fact that it need not be considered at all. 

Fear of Breaking Beet Leaves 

The fear of breaking off some of the beet leaves with the spray 
machines and team often keeps growers from spraying. The presence 
of a very few worms in a field will reduce the leaf surface of a crop much 
more than all the leaves that will be broken off during the spraying. 
The fact that there is only a hole here and there in the leaves makes the 
damage appear slight, but ft does not take many such holes to equal the 
area of a whole leaf, although the loss is not nearly so apparent as when 
the whole leaf is broken off. 

Hard to Realize Danger 

It is often very hard for growers to realize that there' is going to be 
any damage. The worms are small and inconspicuous, which makes 
their numbers appear insignificant as compared with the foliage of the 
beets. If in doubt yourself and the Sugar Company representative 
advises spraying, remember that this man has no interest in your spend- 
ing more money on your crop unless by so doing you can produce a 
better crop. 

DESCRIPTION 
The Egg 

The eggs of the sugar beet webwormmoth (Fig. 5, Plate V, Page 19) are 
about the size of a small pin-head, of a pearly white color when first laid, 
becoming yellowish as the young worm develops within. When depos- 
ited singly they appear as shown at "A" of the figure. They often 

74 



Sugar Beet Webworm 

occur in groups of from two to five or six or even more, when they are 
placed in rows, the eggs overlapping as shown at "B" and "C." 

The Worm 

Figure 3, "A," Plate V, Page 19 shows a young webworm, natural 
size, on a beet leaf. Figure 4, Plate V, Page 19 shows this same worm 
much enlarged. As they grow larger these worms become darker, 
appearing more like the full grown worms. 

The full grown worm is shown enlarged in Figure 6, Plate V, Page 
19. They are not very variable in color, although some individuals 
are somewhat lighter than the figure. The most characteristic marking 
is the dark line in the center of the back with the row of dark circles on 
either side, each with a small bristle in the center. These circles are 
grouped in pairs. When disturbed the worms jerk their bodies violently 
from side to side, often throwing themselves from the leaf. 

The Pupa and Cocoon 

The cocoon (Fig. 8, Plate V, Page 19) is composed of silk which is 
produced by the worm. These silken tubes, which are often 1| to 2 
inches long, reach to the surface of the soil. When removed with the 
earth adhering to them they appear like small earthen rods. The light 
portion of the figure shows where the soil has been scraped away, re- 
vealing the cocoon beneath. 

The pupa (Fig. 9, Plate V, Page 19) is very active. When disturbed 
it will twist and squirm about in very much the same manner as the worm. 
At the tip are eight curved spines, four on either side, as shown in Figure 
10, Plate V, Page 19. 

The Moth 

The moth (shown natural size, Fig. 11, Plate V, Page 19), with 
its delicate shades of gray, brown and tan, harmonizes so well with the 
colors of the soil that when resting on the ground it is hard to distinguish 
from its surroundings. When at rest its wings are folded over the body 
so that the moth is triangular in form like the outline drawing to the left 
of Figure 4, Plate VI, Page 21 . When disturbed the moths fly up, mak- 
ing short, jerky, zigzagging flights. 

LIFE HISTORY 

The first webworm moths appear during the latter part of April and 
early May. About the first of June the moths of this first brood of the 
season are most numerous. 

After mating takes place each female deposits several hundred eggs 
on sugar beets or on lamb's-quarters, Russian thistle, alfalfa and other 
plants growing in the field and along the ditch banks and fence rows. 

At the end of from three to five days hundreds of hungry little worms 
hatch and begin their work of destruction. 

Feeding continues from two to three weeks, the amount eaten 
daily increasing very rapidly until the worms are full grown. During 
the last two or three days before they enter the soil to pupate, the amount 
eaten is appalling. 

75 



Sugar Beet Webworm 

When full grown the worms burrow into the soil and by much 
wriggling and twisting about form a long cell extending from the surface 
to a depth of If to 2 inches. When the cell is completed the worm pro- 
ceeds to line it with silk, which it spins into a tough, leathery cocoon- 
After the cocoon is completed the worm begins to shorten and De- 
comes very much wrinkled. All this time the pupal case has been form- 
ing just under the worm's skin, which breaks and the pupa wriggles its 
way out. 




Fig. 13. A Portion of the Compound Eye of a Tiger-beetle, highly 
magnified. (See page 131) 



While in the pupal stage legs, wings, antennae and a long proboscis 
with which the moth will suck the nectar from the alfalfa and other 
flowers upon which it feeds, two compound eyes, each composed of many 
smaller ones (See Fig. 13), and a covering of feather-like scales, are 
formed. After all this is completed the moth comes forth. 

These moths from the first brood of worms mate and the females lay 
the eggs for the next brood. These worms pass through the same changes 
as the first until they enter the soil. All make cells like those of the first 
brood worms and line them with silk. Only a small portion of them 
pupate in the fall, however. The greater number remain unchanged in 
their cells until the following spring. With the coming of warm weather 
they change to the pupa and after ten days or two weeks, to moths, which 
are the first moths to appear in the spring. 

76 



Sugar Beet Webworm 

The worms which pupate in the fall become moths in about ten or 
twelve days. After breaking out of the silken cocoons these moths mate 
and the females lay eggs for a third brood. When full grown, the worms 
of this brood enter the ground, where they remain in their cocoons, as 
worms, until spring. 

How wisely Nature has provided for the carrying of the beet web- 
worm over the winter! For fear that an early winter overtake the last 
brood in the fall and they perish, a part of the second brood is set aside 
as a sort of sinking fund against such a calamity. There is a considerable 
overlapping of the broods, so that the eggs and several sizes of worms may 
be present at one time. 

NATURAL ENEMIES 
Ichneumon-flies 

The dusky winged parasite 9 (Fig. 7, Plate V, Page 19) is one of the 
most common enemies of the sugar beet webworm. The larva of this 
parasite develops within the webworm, but does not kill it until after it 
has entered the ground and spun its cocoon. Then instead of the moth, 
the parasite emerges from the cocoon. 

This parasite has four dusky wings. Near the center of each of the 
forward pair is a partially clear area. The body is dark reddish or bay 
and the legs have dark bands which give them the appearance of being 
ringed. 

Braconids 

The little wasp-like parasite 3 (Fig. 14, Plate V, Page 19), which is a 
Braconid, frequently emerges from a cocoon instead of the webworm 
moth. 

Tachina-flies 

The Tachina-fly 16 (Fig. 13, Plate V, Page 19) fastens its eggs onto 
the webworm and when the maggots hatch they burrow into it. At first 
the webworm appears to be little disturbed by the maggots, but as the 
latter increase in size their feeding weakens the worm, which finally dies. 
When fully grown, the maggots change to pupae inside the puparium 
(Fig. 12, Plate V, Page 19). The adult fly breaks open the end of the 
puparium, as shown in the figure, and escapes. 

Solitary Wasp 

One of the enemies of the sugar beet webworm belongs to a group of 
wasps known as solitary wasps. (See page 135.) 

This wasp 13 (Fig. 15, Plate VI, Page 21) places its eggs in 
tunnels, one of which is shown in cross section in Figure 14, Page 78. 
These tunnels are dug in the soil about the borders of fields. 

The mouth of the tunnel is always built up a half inch or so above the 
surface of the soil. When the nest is completed several web worms are 
caught and after being stung, which paralyzes them, they are placed at 
the bottom of the tunnel. After a single egg is deposited among the 
worms a wall is built so as to make a small cell at the lower end of the 
tunnel. The chimney-like mouth is next filled with mud. The larva 
which hatches from the egg feeds upon the webworms until ready to 
change to the pupa. This change takes place in the burrow, from which 
the adult w asp escapes by digging its way out. 

(3-9 13-is^ See explanation of "Reference Figures." page 2 

77 



Sugar Beet Webworm 



True Army Worm 



•- ~ i 3*6. *> 




Fig. 14. Cross Section through Burrow of the Solitary Wasp 
Robber-flies 

There is a family of flies commonly known as robber-flies (Fig. 1 2, 
Plate VI, Page 21), the members of which prey upon other flies, as well 
as upon bees and their near relatives, small flying beetles and moths. 
These flies will often be noticed resting on the ground or some object 
which furnishes a clear view of the surroundings, patiently waiting for 
some victim to appear. Their heads are joined to the body by a freely 
moving neck so that they can be moved at will. While waiting for some 
ill-fated fly to appear the head is moved about following the flight of 
passing insects in really human fashion. 

These flies capture their victims by pouncing upon them in true bird 
of prey fashion. Holding the victim with their long legs, the beak is 
thrust into its body and the contents sucked up. One of these flies was 
observed to capture and feed upon a webworm moth. 

(b) TRUE ARMY WORM 

(Figs. 21, 22, 24 and 25, Plate I, Page 11) 

The true army worm is one of those insects which, while always 
present in small numbers in our fields, commonly escapes, unobserved, 
because of its seclusive habits. However, when for any reason the natural 
checks become abnormally scarce or favorable weather conditions prevail 
in connection with a plentiful food supply, it multiplies very rapidly, 
overrunning our fields in vast hordes, often traveling in such large num- 
bers that the very earth seems to move. All follow the same general 
direction, destroying crops as they go, and leaving nothing but the 
riddled remains of what a few days before gave promise of a bountiful 
harvest. 



78 



True Army Worm 

NATURE OF INJURY 

In the case of leaf-eating insects the damage done is usually pro- 
portionate to the amount of leaf surface destroyed. However, the true 
army worm is an exception to this rule. When feeding, these worms 
have the habit of climbing grass and grain stalks and gnawing off the heads. 
When grain is in the shock, especially if harvested a little green, the heads 
are often gnawed off also. For this reason the damage greatly exceeds 
that of most insects of this class in that the army worm destroys much 
more than it actually eats. 

Sugar beets are seldom damaged except where they lie in the path of 
the moving worms or next to infested small grain or grass crops. When 
attacking this crop the worms overrun the leaves, at the same time eating 
irregular areas out of their margins. In case of severe injury all of the 
leaves with the exception of the coarse stems may be destroyed. The 
roots are seldom, if ever, eaten. The army worm usually appears so late 
in the season that few beets are killed. 

METHODS OF CONTROL 
Spraying 

When the nature of the crop attacked is such that poison can be 
applied in the form of a spray, without danger of poisoning either live 
stock or human beings that use the crop as a food, the army worm can be 
effectively controlled by spraying with Paris green or lead arsenate. 
The same proportions of poison and water should be used as in the control 
of the beet webworm ; i. e., 4 pounds of Paris green or 16 pounds of arsenate 
of lead paste to the amount of water used in spraying an acre. Remem- 
ber that the sprayer should be adjusted so as not to apply more than 100 
to 125 gallons per acre. 

Poisoned Bait 

When the food supply has become exhausted and the worms have 
started across country in search of new pasturage, the poisoned bait 
recommended in the control of cutworms will prove most effective. (See 
pages 39 and 40.) This should be scattered in the path of the worms. 
Several strips of a rod or so wide with about the same distance between 
them will give the best results. As the worms are most active during 
the latter part of the afternoon this is the best time to put out the bait ; 
however, if the army is on the move earlier, the poison should be scattered 
earlier. 

Furrow Trap 

This consists of a furrow plowed across the path of the advancing 
worms. The soil should be thrown toward the worms so as to leave the 
perpendicular side of the furrow opposite them. , Post holes should be 
bored in the bottom of the furrow every few feet. As the worms enter 
the furrow they will attempt to climb up the perpendicular side. Many 
failing in this will wander up and down the furrow in search of a place 
where they can climb out. In this way many will fall into the post holes. 
The worms thus trapped can be killed by crushing them with a piece of 
wood or by pouring a small quantity of kerosene into each hole. Some- 
times the post holes are not used. In their stead a small log or heavy 

79 



True Army Worm 

post is hauled up and down the furrow to crush the worms. The furrow 
in connection with the poisoned bait makes a very effective combination. 

DESCRIPTION 
The Egg 

The eggs have a smooth shining surface. When first laid they are 
of a pearly white. As the young worm develops the color changes to a 
creamy flesh color, gradually becoming darker until just before the young 
worm emerges, when it is a dull gray. 

The moths appear to prefer the dense growth of grass or grain which 
commonly grows on old stack bottoms or about manure piles or the 
droppings of animals in pastures, as places to deposit their eggs. Injury 
to small grain is often first observed where this heavy growth occurs 
on old stacking grounds. 

The eggs often occur in clusters of a hundred or more. Usually 
they are deposited in the sheath of grass and grain leaves, sometimes 
between two leaves which happen to be fastened together. Egg laying 
takes place during the night. A single female moth has been known to 
lay 254 eggs, and as many as 800 developed and undeveloped eggs have 
been taken from the abdomen of one moth.* 

The Worm 

In from eight to ten days after the eggs are laid, the young worms 
appear. As they emerge from the egg they are whitish with brown heads. 
The first act of the newly hatched worm is to eat the shell of the egg from 
which it has just escaped. 

During the course of their development the worms shed their skins 
several times. As soon as the worm has cast off its old coat it proceeds 
to devour it as if attempting to cover up its trail. 

The full grown worms (Figs. 21 and 22, Plate I, Page 1 1) are variable 
in color, some being considerably lighter than the figures. The figures 
are so lifelike that a description of the coloring is not necessary. When 
disturbed the worms curl up as shown in Figure 21. This is not char- 
acteristic of the army worms alone, however, as many caterpillars, espec- 
ially cutworms, have the same habit. When fully grown the army worms 
enter the soil, where they form a cell in the same way as the cutworms. 
In this cell the worm spins a thin, silken cocoon within which it changes 
to the pupa. 

The Pupa 

The pupa (Fig. 24, Plate I, Page 11) of the army worm does not 
differ greatly from that of the cutworms already mentioned. At first it 
is a light creamy yellow. When fully colored it is of a rich mahogany 
brown. At the tip there are four spine-like appendages as shown in the 
figure. After spending from two to three weeks in the pupal stage the 
moths appear. 

The Moth 

The moth (Fig. 25, Plate I, Page 11) is a night flyer and is seldom 
seen on the wing during the day unless the weather is cloudy and damp. 

*Davis and Satterthwait, "Life History Studies of Cirphis unipuncta, the True Army Worm," Journal 
of Agricultural Research, Vol. VI, No. 21 (1916). 

80 . 



True Army Worm Alfalfa hooper 

The most characteristic marking is the white spot near the center of each 
fore wing. The last part of the army worm's Latin name, "unipuncta," 
is derived from this spot and means one point. 

LIFE HISTORY 

So far as known, the army worm passes the winter, in the north- 
ern half of the United States, as a partially grown worm or larva. 
The first moths appear during May or June, depending upon the season 
and the locality. The cooler the season and the farther north we go the 
later they appear. 

The eggs are laid soon after the moths emerge, and the young worms 
appear during June. These feed for about three weeks and then change 
to pupae, in which form they remain from eight to eleven or twelve days, 
when the adult moths come forth. 

The second brood is in the egg stage about the middle of July, in the 
worm stage during the latter part of July and early August, in the pupal 
stage during the latter part of August, and the moths issue between the 
the last of August and the 8th or 10th of September. 

The third brood of worms hatches during the latter part of Septem- 
ber and early October. These worms spend the winter as partially 
grown larvae and complete their development the next April. 

In the southern part of the country a fourth generation may occur. 

NATURAL ENEMIES 
Parasitic Flies 

Several species of parasitic flies destroy the army worm. Two 
species, "Archytus apicifere Walk" and a "Winthemia"* species (near 
militaris Walsh) have been bred from parasitized army worms taken 
in Boulder County, Colorado. 

Birds 

Birds, especially blackbirds, meadow larks and other ground feeding 
species, render valuable service in destroying these worms. 

Ground Beetles 

Ground beetles and their larvae also devour large numbers of army 
worms. 

(c) ALFALFA LOOPER 

(Figs. 5, 6, 7 and 8, Plate VI, Page 21) 

The first authentic record of this insect as a crop pest** states that 
during June, 1895, considerable damage was done to alfalfa near Grand 
Junction, Colorado, by the caterpillars. Again in 1914 reports of injury 
by this insect came from the same locality. The same year the looper 
also appeared in large numbers in the Yellowstone Valley in Montana 
and in adjoining territories, where considerable damage was done to both 
alfalfa and sugar beets. The latter were damaged only in those instances 
where the worms migrated from alfalfa fields or the sweet clover growing 
on waste land. 



*Determined by C. H. T Townsend. 
**J. A. Hyslop. "The Alfalfa Looper." Bulletin No. 95. Part VII. Bureau of Entomology. U. S. 
Department of Agriculture (1912). 

81 



Alfalfa Looper 

NATURE OF INJURY 

The injury to sugar beets is similar to that caused by other leaf- 
eating caterpillars. The destruction of the leaves reduces the yield and 
sugar content of the crop. 

Both the leaves and blossoms of alfalfa are eaten. This reduces the 
yield and quality of hay. The destruction of the blossoms reduces the 
yield of seed where the crop is grown for seed production. 

METHODS OF CONTROL 

As this insect seldom if ever attacks sugar beets until its favorite 
food plants (alfalfa and sweet clover) are exhausted, such attacks can be 
anticipated and preventive measures employed to protect the crop. 

Furrow Trap 

In case sugar beets adjoin infested alfalfa or waste land overgrown 
with sweet clover the furrow trap recommended for the control of the true 
army worm (page 79) can be used with good results. The furrow should 
be thrown away from the beets so as to leave the perpendicular side next 
to them. If water is available a small stream in the furrow will add to 
its effectiveness. 

Poisons 

Where the loopers are feeding on alfalfa or sweet clover growing on 
ditch banks or fence rows about beet fields these plants should be sprayed 
with Paris green or arsenate of lead, using 2 to 3 pounds of the former or 
8 to 1 2 pounds of the latter if the paste is used, or 4 to 6 pounds of the dry 
form, to 50 gallons of water. 

If the caterpillars have entered a beet field, spray the beets, using 
the proportions of poison and water given above. 

Bunches of freshly cut green alfalfa or sweet clover, sprayed with 
Paris green and placed in the furrow, where the furrow trap is used, will 
kill many of the loopers. 

Mowing 

Where alfalfa is being damaged it should be mowed at once. The 
longer it stands the poorer the quality will be. After the hay is removed 
the stubble should be sprayed to destroy the worms and protect the new 
growth. 

If strips of alfalfa are left uncut at intervals through the field the 
loopers will congregate on these and can then be killed by spraying the 
standing alfalfa. When the worms have been destroyed the alfalfa on 
the strips can be removed. This hay should not be fed unless heavy 
rains have washed off the poison. 

Close watch should be kept of the worms after the infested hay is 
cut to prevent their migrating to adjoining crops. 

DESCRIPTION 
The Egg 

The eggs are pale yellow, hemispherical in shape, rounded at the base, 
the apex with a rounded depression, and are finely creased vertically.* 

*J. A. Hyslop, "The Alfalfa Looper," Bulletin No. 95, Part VII, Bureau of Entomology, U. S. 
Department of Agriculture (1912). 

82 



Alfalfa hooper 

The eggs are deposited on the food plants. Moths have been ob- 
served in the act of laying at three o'clock in the afternoon.* 

The Caterpillar 

These caterpillars differ from all others discussed in this Bulletin 
in having but three prolegs on each side of the posterior half of the body. 
By comparing Figure 1 and Figure 5, Plate VI, Page 21, this difference is 
made more apparent. It will be noticed that Figure 1 has four legs just 
back of the center, and one at the tip of the body, and that Figure 5, which 
represents a full grown alfalfa looper, has but three including the one at 
the tip. 

The alfalfa loopers vary greatly in color. 

The darker parts of different individuals range from a dark olive 
brown to pale greenish brown. The figure represents one of the lighter 
type. 

The Cocoon 

The cocoon (Fig. 6, Plate VI, Page 21) is made of several leaves of 
the host plant held together by loosely woven silk threads. Sometimes 
the cocoons are constructed among dead leaves and trash on the ground. 

The Pupa 

After the worm has completed its cocoon it changes to the pupa 
within it. The pupa (Fig. 7, Plate VI, Page 21) is very similar to those 
of the cutworms and army worms. 

The Moth 

The adult (Fig. 8, Plate VI, Page 21) is one of our most beautiful 
moths. The figure is so true to life that no description is necessary. 
The silvery spot near the center of the fore wing is characteristic of this 
and related moths. 

LIFE HISTORY 

This insect probably passes the winter in hibernation in the pupal 
stage. During the latter part of May and early June the eggs for the first 
brood of worms of the season are laid. 

The length of the egg stage is not definitely known. The worms 
feed for about two weeks, at the end of which time the cocoon is made 
and the change to the pupal stage takes place. This lasts about ten to 
twenty days during ordinary summer weather. 

The first adults of the second brood appear during late June and early 
July. There are two and possibly three generations each season. 

NATURAL ENEMIES 

The alfalfa looper appears to be a favorite host of many parasites. 
The Ichneumon-fly 8 , shown in Figures 9 and 10, Plate VI, Page 21, was 
reared from alfalfa loopers taken at Edgar, Montana, and several other 
species have been reared from alfalfa loopers by Mr. Hyslop. 

Many of the caterpillars succumb to a bacterial disease. The in- 
fected worms become dark in color soon after dying. The dead worms 

*Mr. Koebels, Bureau of Entomology Notes, No. 95-K. 
( s ) See explanation of ' 'Reference Figures." page 2. 

83 ! 



Alfalfa hooper Alfalfa Webworm 

hang limp from the host plant at first, but finally the body becomes so 
decayed that it drops to the ground. 

(d) ALFALFA WEBWORM* 

(Figs. 1, 2, 3 and 4, Plate VI, Page 21) 

During the summer of 1914 the alfalfa webworm 1 appeared in 
large numbers in Northern Colorado, where it did considerable damage 
to first cutting alfalfa. While they appear to prefer this crop and sweet 
clover, the worms caused some anxiety among sugar beet growers by 
feeding upon the leaves of sugar beets. 

NATURE OF INJURY 

When attacking alfalfa the worms spin masses of whitish web at the 
tips of the plants, inclosing the new, tender leaves and blossoms. This 
web furnishes protection for the worms while they feed upon the inclosed 
parts. 

Injury to sugar beets is similar to that caused by the sugar beet web- 
worm. Some of the leaves will be found partially covered by a web which 
terminates in a long tube extending to the ground, the lower end being 
among the clods on the surface. When but few worms are present there 
is usually only one to a plant. 

METHODS OF CONTROL 
Poison 

This worm can be controlled on sugar beets by spraying with any 
arsenical poison. The same amounts of poison should be used as for the 
control of the sugar beet webworm (pages 72 and 73), and should be 
applied in the same way. 

Mowing 

In case alfalfa is being damaged it should be cut at once, cured and 
put up to prevent loss. After removing the crop the stubble can be 
sprayed. (See "Mowing," page 82.) 

Irrigation 

Irrigating after the worms have entered the ground to pupate will 
seal them in, preventing many moths from emerging when mature. 

DESCRIPTION 
The Worm 

Although closely related to the sugar beet webworm, this worm 
(Fig. 1, Plate VI, Page 21) is easily distinguished from it by its coloring. 
The central portion of the back is occupied by a light stripe tinged with 
flesh color. On either side of this there is a dark stripe about the same 
width. Along the upper and lower margins of these dark stripes there 
are several dark circular spots, each bearing a hair-like bristle. With 
the exception of those segments next to the head and at the tip of the 
body, each segment has three of these spots, two on the upper border of 

*This is a local name applied to this insect in Northern Colorado. This insect should not be con- 
fused with " Loxostege similaris Guen." which is also called the alfalfa webworm. (See Bulletin 109. Okla- 
homa Agricultural Experiment Station. February. 1916). 

(') See explanation of "Reference Figures," page 2. 

84 



Alfalfa Webworm 

the dark stripe and one on the lower. Just below the dark stripe is an- 
other light, more or less flesh-colored one, and below this the body is 
dusky, but not so dark as the other dark portions. There are several 
dark circles within the dusky portion, each bearing a bristle. The lateral 
portions of the first segment back of the head are dark. The head is 
mottled with dark brown on a lighter ground color. 

The worms are very active. If their webbed retreats on alfalfa are dis- 
turbed they throw themselves to the ground or run rapidly down the 
stems. 

When on sugar beets they will be found concealed at the end of the 
long, silken tube already mentioned, among the clods near the crown of 
the plant. If the soil is disturbed the worms run rapidly to the web 
among the leaves, and if disturbed here they descend to the end of the 
tube again just as rapidly. They appear to travel backward as freely as 
forward. 

The Pupa 

When fully grown the worms enter the soil and spin a cocoon very 
similar to that of the sugar beet webworm, but more loosely made, in 
which they change to the pupa (Fig. 2, Plate VI, Page 21). The pupa is 
very much like that of the beet webworm, but can be readily distinguished 
from it by the eight spatulate (spoon-shaped) appendages at the tip (Fig. 

3, Plate VI, Page 21), those of the sugar beet webworm being curved and 
pointed. 

The Moth 

In warm weather the moths appear in about six or eight days after 
the worms change to pupae. By comparing the figure of this moth (Fig. 

4, Plate VI, Page 21) with that of the sugar beet webworm (Fig. 11, 
Plate V, Page 19), the differences are clearly brought out. It will be 
noticed that the under wings of the alfalfa webworm are much darker 
than those of the sugar beet webworm moth and that the markings of the 
upper or fore wings are darker as well as different in form. Flying in the 
field the two are very hard to distinguish from each other. 

LIFE HISTORY 

So far as known to the writer, there are no published accounts of the 
life history of this insect. In general it is probably quite similar to that 
of the sugar beet webworm. The injury to alfalfa referred to above 
occurred during the last of June. The moths of this brood appeared July 
14th. During August another brood of worms appeared. This second 
brood was not so numerous and did less damage than the first. In all 
probability, in the latitude of Denver, the winter is passed in the larval 
or pupal stage. 

NATURAL ENEMIES 

An undescribed Tachina-fly, 15 (Fig. 11, Plate VI, Page 21), was 
reared from caged worms. 

Birds and poultry no doubt do much to hold this insect in check. 

( 10 ) See explanation of "Reference Figures," page 2. 

85 



Yellow-bear Caterpillar 



(e) YELLOW-BEAR CATERPILLAR 

(Figs. 15 and 16, Plate V, Page 19) 

The yellow-bear caterpillar is always in evidence, in small numbers, 
on Russian thistle, lamb's-quarters and other weeds along the fence 
rows, ditch banks and roadsides. As a rule they are not numerous enough 
to cause noticeable damage to crops. Occasionally, however, they become 
so numerous that the wild food plants are not sufficient for their support. 
At such times the caterpillars attack whatever growing crop happens to 
be nearest at hand. Such an outbreak occurred during August and Sep- 
tember, 1909, in the Arkansas Valley in Southern Colorado.* 

NATURE OF INJURY 

When young the worms eat only the surface of the leaves but as they 
become older and larger the margins of the leaves are eaten away and holes 
are eaten into them. When very numerous, crops are completely defoli- 
ated by these caterpillars, or in the case of sugar beets the stems, midribs 
and young heart leaves only are left untouched. Severe attacks on sugar 
beets result in a lowering of the yield and sugar content of the crop. 

The yellow-bear is one of the most general feeders among the whole 
list of crop pests. The following list of plants injured is given by Mr. 
Marsh in the bulletin alreadv referred to : 



Radish 

Celery 

Carrot 

Parsnip 

Egg plant 

Potato 

Pumpkin 

Dahlia 

Cherry 

Gooseberry 

Blackberry 

Raspberry 

Currant 

Grape 

Dock (Rumex) 



Squash 

Watermelon 

Cantaloupe 

Sweet potato 

Corn 

Lima bean 

String bean 

Amaranthus 

Chenopodium 

Helianthus 

Solanum rostratum 

Verbesina 

Ambrosia 

Russian thistle 

Spanish needle 



Sugar beet 

Stock beet 

Table beet 

Rhubarb 

Cabbage 

Cauliflower 

Turnip 

Asparagus 

Pea 

Peanut 

Alfalfa 

Hollyhock 

Morning-glory 

Canna 

Hyacinth 

METHODS OF CONTROL 
Poison 

In his work in the Arkansas Valley of Colorado, Mr. Marsh exper- 
imented with both Paris green and arsenate of lead. It was found that 
arsenate of lead, even where applied in quantities as high as 8 pounds to 
100 gallons of water, was of little value in the control of the yellow-bear 
caterpillar. Paris green used at the rate of 10 pounds to 100 gallons of 
water to which 10 pounds of lime was added to prevent injuring the 
leaves killed practically all caterpillars in three days. 

From the results of this work it appears that this worm is very resist- 
ant to arsenical poisoning, the ordinary amounts being practically value- 
less in its control. 

*H. O. Marsh. "Biologic and Economic Notes on the Yellow-bear Caterpillar," Bulletin No. 82. 
Part V. Bureau of Entomology, U. S. Department of Agriculture (1910). 

86 



Yellow-bear Caterpillar Zebra Caterpillar 

DESCRIPTION 
The Egg 

The eggs are laid in clusters on some green plant. In the Arkansas 
Valley Mr. Marsh found large numbers of eggs on rhubarb, which appears 
to be a favorite food plant. 

The Caterpillar 

Unlike the cutworms and the other caterpillars so far considered in 
this Bulletin, the yellow-bear is completely covered with a coat of tawny 
hair. This varies from a reddish brown in the darker individuals to a light 
yellow or straw color in the lighter ones. Figure 15, Plate V, Page 19 
represents one of the lighter type. The body of the caterpillar is most 
often pale yellow or straw color with a darker stripe running lengthwise 
on either side. 

The Pupa 

The pupa is more robust than that of the cutworms already men- 
tioned. Instead of entering the ground to pupate the worms seek some 
secluded place such as underneath boards and other objects lying on the 
ground or among the dead leaves and trash about the borders of fields 
and on ditch banks. Here the caterpillar. forms a loose cocoon composed 
almost entirely of its own hairs held together by threads of silk, within 
which it changes to the pupa and later to the moth. 

The Moth 

The adult yellow-bear (Fig. 16, Plate V, Page 19), sometimes known 
as the Virginian tiger-moth, is one of our most delicate night fliers. Pure 
white with dark spots on the wings and three rows of black dots on the 
body alternating with two yellow stripes, this moth presents a striking 
contrast to the dusky winged cutworm moths. 

LIFE HISTORY 

This moth spends the winter in the pupal stage concealed under 
trash along fence rows and ditch banks and on other waste ground. The 
moths appear in early summer to deposit the eggs for the first brood of 
worms, which become mature about the last of July. The second brood 
appears during August and becomes fully grown about the first week of 
September. These worms pupate after spinning the loose cocoon already 
mentioned and remain in this form until the next spring. 

NATURAL ENEMIES 

The natural enemies of the yellow-bear appear to be peculiarly few. 
Because of their covering of hair few birds feed upon them. Certain 
Tachina-fiies destroy a few worms and in some localities many die of a 
fungous disease.* 

(f) ZEBRA CATERPILLAR 
(Fig. 11, Plate III, Page 15) 

This is one of our most striking caterpillars. When resting on a 
beet with its bright colors contrasted with the dark green of the leaves 
it is almost a thing of beauty. 

*Botrytis bassiana Bals. 

87 



Zebra Caterpillar Leaf-eating Beetles 

NATURE OF INJURY 

The zebra caterpillar bears the distinction of being the first insect 
reported as damaging beets in the United States.* While it seems to 
prefer vegetable crops, especially beets, and cabbage, turnips, and other 
cruciferous plants in general, yet it feeds upon field crops and even the 
leaves of trees and shrubs. 

METHODS OF CONTROL 

Dr. Chittenden* states that this insect yields readily to sprays of 
arsenicals. Paris green or arsenate of lead, the former at the rate of 2 to 
3 pounds and the latter at 4 to 6 pounds dry or 8 to 12 pounds of the 
paste, to each 100 gallons of water, will give satisfactory results. 

DESCRIPTION 
The Egg 

The eggs are deposited in clusters of from several to as many as a 
hundred or more, usually on the under side of the leaves of the food plants. 

The Caterpillar 

At first the worms are whitish in color with dark heads and several 
dark spots scattered over the .body. While small they feed in compact 
groups, but after several days the skin is shed and the caterpillars take on 
the colors of the adult worm (Fig. 11, Plate III, Page 15) and gradually 
become scattered. When disturbed the worms coil up and fall to the 
ground. 

The Moth 

The moth is about the size of the adult western army cutworm (Fig. 
3, Plate I, Page 11). The fore wings are a chestnut brown shaded with 
purplish brown. The hind wings are whitish with pale brown margins. 

LIFE HISTORY 

The zebra caterpillar passes the winter in the pupal stage in the 
ground. The first moths appear in May and June. In moderate tem- 
peratures the eggs hatch in about six days. The worms feed four or five 
weeks and then change to pupae, in which form they remain for about 
sixty days. The moths of the second brood appear in late August or 
September. The second brood of worms feeds during the fall, the change 
from worm to pupa taking place before winter sets in. 

NATURAL ENEMIES 

This caterpillar appears to be especially attractive to the various 
parasitic insects infesting caterpillars in general. Many are killed by 
fungous diseases, while birds no doubt destroy them in large numbers. 

2. LEAF-EATING BEETLES 

There is a family of variously colored beetles of small or moderate 
size, the members of which are called "leaf-beetles" because they feed 
upon the leaves of plants in both the adult and larval stages, with a few 

*Dr. F. H. Chittenden, "A Brief Account of the Principal Insect Enemies of the Sugar Beet." Bulle- 
tin No. 43. Division of Entomology. U. S. Department of Agriculture (1903). 

88 



Leaf-eating Beetles Larger Sugar Beet Leaf-beetle or Alkali-beetle 

exceptions where the larvae are root feeders. The Colorado potato-beetle 
is the best known representative of this family. 

Several leaf-beetles feed upon sugar beets and under certain con- 
ditions do considerable damage to the crop. The principal species of 
this family, together with other leaf-eating beetles attacking sugar beets 
in the Great Plains area, are discussed in the following pages. 

(a) LARGER SUGAR BEET LEAF-BEETLE OR ALKALI-BEETLE 

(Figs. 1 to 5, Plate VII, Page 23) 

In Northern Colorado this beetle is known as the "alkali-beetle" 
or "alkali-bug", from the fact that it breeds most freely on the weeds 
growing on low, damp ground where the alkali is brought to the surface 
by seepage. In some other parts of its range it is known as the "French 
bug". 

NATURE OF INJURY 

Both the larvae and the adults damage sugar beets. Injury usually 
occurs on the border of fields next to waste land which is damp and con- 
tains an excessive amount of alkali. The adults are very active on the 
wing and often appear in swarms in the center of fields or at considerable 
distances from low wet ground. When few in number their work appears 
very similar to that of the flea-beetles only that the holes in the leaves 
are larger. (See Fig. 1, Plate IV, Page 17). In severe cases nothing but 
a network composed of the larger veins of the leaves is left and the leaf 
becomes brown and shriveled. 

METHODS OF CONTROL 
Spraying or Burning Weeds 

When beets are planted near low, damp ground the weeds on this 
waste land should be watched closely in early summer. If alkali-beetles 
and their larvae appear in numbers the weeds should be sprayed with 
Paris green or straw should be scattered among them and burned. 

The destruction of the beetles and larvae at this time will prevent 
their migrating into the beet fields and will also reduce the number of 
eggs laid later. 

Spraying Crop 

In case the beetles and larvae have already begun to damage beets, 
Paris green should be applied as a spray, using 4 pounds to 100 gallons of 
water. Many times it happens that only a small portion of the field is 
being damaged, making it inconvenient to use a team and power sprayer. 
In such case a knapsack sprayer (See page 36) can be used to advantage. 

Paris Green Applied Dry 

Good results have followed a dry application of Paris green. If to 
be applied in this way mix at the rate of 1 pound of the poison to 10 
pounds of low grade flour or finely pulverized air-slaked lime. This 
mixture can be dusted over the beets by using a sack made of coarse cloth 
or a tin shaker with the bottom perforated with rather small holes. Best 
results are secured if the dusting is done early in the morning when the 

89 



Larger Sugar Beet Leaf-beetle or Alkali-beetle Western Beet Leaf-beetle 

dew is still on the beets. Never attempt to apply the dry poison when 
the wind is blowing. Always spray or dust the beets some distance be- 
yond where the insects are feeding. 

DESCRIPTION 
The Egg 

The brownish gray eggs (Fig. 3 enlarged and Fig. 4 about natural 
size, Plate VII, Page 23) are usually placed in clusters on the under side 
of the leaves of the food plants. Russian thistle and saltbush, both of 
which abound on alkali ground, are favorite plants on which to deposit 
the eggs. 

The Larva 

The young alkali-bug is sluggish in its movements. In color it is a 
dirty gray at first, becoming darker with age. When fully grown it ap- 
pears as in Figure 1, Plate VII, Page 23. At this time the ground color 
is an olive brown. The entire body is covered with blunt tubercles 
each bearing several short, stiff hairs. These tubercles are yellowish in 
color, giving the larva a spotted appearance. 

The Pupa 

The pupa (Fig. 2, Plate VII, Page 23) is what is known as a "free 
pupa" because the legs and other parts of the insect are encased separ- 
ately, in contrast with the pupae of the cutworms and other related insects. 
The pupal stage is passed in a small oval cell in the soil. At first the pupa 
is a uniform yellowish brown as shown in the figure, but just before the 
adult emerges the color becomes darker. 

The Beetle 

The adult alkali-beetle (Fig. 5, Plate VII, Page 23) often occurs in 
swarms. In color it varies from a light brownish yellow to almost black. 
Sometimes the wing covers are quite distinctly striped, the dark color 
being concentrated near the center of each. The figure represents an 
intermediate color type. 

(b) WESTERN BEET LEAF-BEETLE 

(Fig. 6, Plate VII, Page 23) 

As the name indicates, this beetle is a Western insect. It is more 
common on the Pacific coast than in the Rocky Mountain regions. It 
first attracted attention in the years 1900 and 1901 in Oregon.* 

This beetle (Fig. 6, Plate VI I, Page 23) is very similar to the "larger 
sugar beet leaf -beetle" in coloring but is only slightly more than one-half 
as large. Its habits appear to be similar to those of the preceding species. 

NATURE OF INJURY 

The only cases known to the writer where this beetle has injured 
sugar beets have been near low, damp ground, the beetles alone damaging 
the crop. The early stages have not been observed by the writer. 

*Dr. F. H. Chittenden, "A Brief Account of the Principal Insect Enemies of the Sugar Beet," Bulle- 
tin No. 43, Division of Entomology, U. S. Department of Agriculture (1903). 

90 



Western Beet Leaf-beetle Flea-beetles 

METHODS OF CONTROL 

The same control measures employed against the preceding species 
should be used in case this insect attacks sugar beets in sufficient num- 
bers to damage the crop. 

(c) FLEA-BEETLES 

The individuals of one group of leaf-beetles are characterized by hav- 
ing the joint of the hind legs next to the body much enlarged. This 
enables them to jump long distances. The habit these beetles have of 
making sudden leaps whenever disturbed suggested the popular name 
"flea-beetle" which is applied to the members of this group. 

Most flea-beetles are small, but some species are of moderate size. 
The color is variable, some species being dull black or brown; others are 
shining black, often with a metallic sheen; some are deep shining blue; 
while in others parts of the insect are red or yellow or striped. 

These active little insects are familiar objects to every person en- 
gaged in either gardening or farming, appearing in swarms on crops dur- 
ing spring and early summer. Several species attack sugar beets, often 
threatening serious damage. 

NATURE OF INJURY 

The work of flea-beetles is quite characteristic. The leaves of the 
plants attacked are eaten full of small holes popularly known as "shot 
holes" (Fig. 1, Plate IV, Page 17). The leaves of the seedling beets are 
sometimes completely destroyed. In severe cases the plants may be 
killed. Usually, however, plants which appear dead will put forth new 
leaves in the course of a week or ten days. 

METHODS OF CONTROL 
Destroy Weeds 

Flea-beetles, in both the adult and larval stages, feed upon many of 
our common weeds. Clean culture, especially keeping down all weeds 
along fence rows and ditch banks, will effectively check the multiplica- 
tion of this pest. Poverty-weed is a favorite food plant of the banded 
flea-beetle. (See page 92). 

Spraying 

Beets are usually attacked while still quite small. For this reason 
spraying is seldom advisable, since the plants will often be stripped of 
their leaves before the beetles have eaten enough poison to kill them. 

Scattering 

The beetles are easily disturbed and the swarms readily scattered 
either by the hand labor while thinning or by the cultivator in cultivating. 
In case the beetles appear in a field before the beets are thinned, it is al- 
ways advisable to disperse them before this work is done. This can be 
accomplished by cultivating the field. If pieces of rope or strips of can- 
vas are fastened to the frame of the cultivator so as to drag on the ground 
the insects will be more completely scattered. 

91 



Flea-beetles Banded Flea-beetle 

Irrigation 

The beetles dislike damp ground. Advantage can be taken of this 
fact, especially in dry years. If the beets are irrigated the insects will 
usually leave the field. The irrigation will stimulate the young beets so 
that they will outgrow the damage more quickly and completely. In 
case irrigation is resorted to great care should be exercised to prevent 
flooding the field as flooding young beets is injurious to them. 

Poison 

In cases where the use of poison is advisable Paris green mixed as 
recommended in the control of the alkali-bug (page 89) should be used. 
If the area to be treated is not too large, Paris green applied dry, mixed 
with ten parts of low grade flour, will give very satisfactory results, 
especially if the plants are small. 

According to Dr. Chittenden,* Paris green mixed with Bordeaux 
mixture gives better results than the Paris green and water spray. As a 
rule spraying the upper surface is sufficient, but for some species attack- 
ing truck crops the under surface must also be sprayed. 

(c-1) BANDED FLEA-BEETLE 

(Fig. 2, Plate IV, Page 17) 

About the time early beets are ready to block and thin, swarms of 
banded flea-beetles (Fig. 2, Plate IV, Page 17) often appear in the fields. 
Seldom is the whole field affected at one time, however. The beetles 
being very active, the same swarm may appear in several places in a field 
within a short time, thus causing considerable damage. Poverty-weed 
is a favorite food plant of this beetle. Damage to beets is most apt to 
occur in fields where this weed is growing. 

DESCRIPTION 
The Egg 

Dr. Chittenden, in the bulletin already referred to,* states that the 
eggs are laid in June and July. They are about one-fourteenth of an inch 
long, elliptical in form and of a light buff-yellow color. 

The Larva 

The larva is a slender, whitish grub. The body is narrowest at the 
head, gradually widening toward the opposite end. The extreme tip of 
the body tapers abruptly, ending in a prolonged process which bears 
several stiff hairs. In this stage the flea-beetles feed upon the roots of 
some crops and weeds. 

The Adult 

The adult beetle (Fig. 2, Plate IV, Page 17) is slightly more than one- 
eighth of an inch in length. The color is somewhat variable. A char- 
acteristic marking is the yellow stripe on each wing cover. The figure 
represents one of the darker colored individuals. 

*Dr. F. H. Chittenden, "'A Brief Account of the Principal Insect Enemies of the Sugar Beet." Bulle- 
tin No. 43, Division of Entomology, U. S. Department of Agriculture (1903). 

92 



Banded Flea-beetle 
Potato Flea-beetle Three-spotted Flea-beetle 

LIFE HISTORY 

The life history of this beetle is imperfectly known. It is thought 
that the winter is passed in the larval stage only. The adults are most 
numerous in June and July, during which months mating and egg laying 
take place. There is no positive evidence of a second brood. 

(c-2) POTATO FLEA-BEETLE 

(Fig. 5, Plate IV, Page 17) 

Not infrequently swarms of the potato flea-beetle appear in fields of 
sugar beets, causing considerable damage to small areas. At such times 
the injury to the crop is similar in every way to that caused by the striped 
flea-beetle and the same remedies should be applied. 

This insect's liking for potatoes is indicated by its common name 
"potato flea-beetle," while its habit of attacking cucumbers and related 
plants suggested the second part of its scientific name, "cucumeris." 

DESCRIPTION 
The Larva 

The larvae are small, whitish grubs which feed in the roots of several 
common wild plants all belonging to the same family as the potato. The 
roughened condition of potatoes known as "pimply" potatoes is caused 
by the larvae burrowing into the tubers. 

The Adult 

The adult beetles (Fig. 5, Plate IV, Page 17) are a dull black with 
the exception of the legs and antennae, which are yellowish. The wing 
covers are clothed with very fine hairs and their surface is covered with 
small punctures which are arranged in rows. The thorax has a deep, 
curved depression across the posterior margin, as shown in the figure. 
The small outline drawing at the left of the figure is the natural size of 
the adult. 

LIFE HISTORY 

The eggs are deposited on the roots of the host plants during May 
and June by the adult beetles, which have spent the winter in hibernation 
under dead leaves and other trash along ditch banks, fence rows and 
roadsides. 

The larvae tunnel into the roots of the host plants, where they feed 
until fully grown. The mature larvae form small, oval cells in the soil, 
near the roots of the plants within which they fed, and change to pupae. 

(c-3) THREE-SPOTTED FLEA-BEETLE 

(Fig. 6, Plate IV, Page 17) 

The three-spotted flea-beetle (Fig. 6, Plate IV, Page 17) is conspicu- 
ous in beet fields in early spring mainly because of its size and coloring. 
It is one of the largest flea-beetles and is readily distinguished by the 
yellowish-red thorax bearing three black spots. 

Lamb's-quarters and related plants, such as Russian thistle and sugar 
beets, appear to be favorite food plants of this species. 

Seldom, if ever, does this beetle occur in great enough numbers to 
require the application of remedial measures. 

93 



Spinach Carrion-beetle 

(d) SPINACH CARRION-BEETLE 

(Figs. 10 and 11, Plate VII, Page 23) 

The spinach carrion-beetle belongs to a family of insects the greater 
part of whose members feed upon decaying animal matter. These 
beetles are common objects under the carcasses of dead animals lying on 
the ground. 

A few species of this family, however, feed upon vegetable matter, 
and some on fungi, while others, like the species under discussion and 
its near relative, the black carrion-beetle (Schwarze Aaskafer) of Ger- 
many, feed upon sugar beets and other crops and upon field weeds. 

From field observations it seems quite probable that the growing of 
sugar beets is not responsible for the presence of this pest in a neighbor- 
hood, but that its presence is due to some of its favorite host plants being 
in the vicinity. 

The following plants make up the menu of this beetle: Lamb's- 
quarters, green-berried nightshade, spinach, and sugar beets. Squash 
and pumpkin vines are sometimes damaged. The adults also feed upon 
alfalfa. 

If none of the weeds upon which it feeds are growing in a neighbor- 
hood the spinach carrion-beetle is not apt to occur in injurious numbers. 

NATURE OF INJURY 

Both the adult beetles and the larvae feed upon sugar beets. The 
edges of the leaves are eaten, the injury being quite characteristic in its 
appearance. According to Prof. R. A. Cooley,* the gnawed margins of 
the leaves are ragged, often showing a thin projection of crushed tissue. 

Injury to sugar beets most often occurs near roadsides, ditch banks, 
fence rows, and grain and alfalfa, from which the insects migrate into the 
beet fields. 

Sugar beets are seldom injured after they have attained any size. 
The greatest damage occurs about blocking and thinning time, when 
many plants may be completely gnawed off. 

METHOD OF CONTROL 

Clean Culture 

Much can be done to control this pest by destroying the weeds upon 
which it feeds. However, the work should not end here. The beetles 
hibernate in the soil along ditches, fence rows and roadsides. If all weeds 
are burned from these waste lands and the soil thoroughly disced or 
plowed in the fall, few beetles will select these bare spaces for hibernation. 
If the weeds and trash are left, these places are inviting hibernating 
grounds, especially if a few of the host plants already mentioned are 
growing on them. 

Poisoned Bait 

In the article* already referred to, Prof. Cooley states that the 
poisoned bran mash so effective in the control of cutworms (See "Kansas 
Mixture," page 39) is very effective against the carrion-beetle when 

*"Spinach Carrion-beetle." Journal of Economic Entomology, Vol. 10, No. 1 (1917). 

94 



Spinach Carrion-beetle 

spread on waste land, about ditches and fields. As the beetles and larvae 
feed principally at night the poisoned bait to be most effective should 
be put out late in the day. 

DESCRIPTION 
The Egg 

The eggs, which are laid in the soil, vary from almost spherical to 
oval in form. The size is also variable. The smaller ones are about ^j 
of an inch long and the larger ones -g\ of an inch long. The color is a 
creamy white, and the surface is polished and glistening. Prof. Cooley 
has observed that the eggs increase in size after being laid. 

The Larva 

The newly hatched larva is about f\ of an inch long and black in 
color. When fully grown the larva appears as shown in Figure 1 1, Plate 
VII, Page 23. The color is a shining black. The head of the insect 
represented by the figure is bent downward, making it appear as 
though the first segment of the thorax were the head. The young car- 
rion-beetles are flat, and the body, which is composed of plates each 
terminating in an acute angled corner at each side, has the appearance 
of being notched on the margin. 

The Pupa 

The pupa is white and soft. The legs, antennae and wings are free. 
At the sides of the body there are several long hairs and at the tip are 
two fleshy prongs also terminated by long hairs. 

The Adult 

The adult beetles (Fig. 10, Plate VII, Page 23) are uniformly dull 
black. The wing covers are ribbed lengthwise. The Latin name of the 
beetle, "bituberosa," meaning "with two tubercles," was suggested by 
the tubercles at the end of the two outside ridges. 

LIFE HISTORY 

Egg laying begins about the middle of May and continues until 
nearly the middle of July. The females seem to prefer moist soil as a 
place to deposit their eggs, which are laid from one to two inches below 
the surface. Prof. Cooley reports as high as 75 eggs from one female, 
the average of several being 39. The eggs hatch in from three to six 
days. 

The larval stage lasts about 24 days, at the end of which time the full 
grown larva enters the ground, forms an oval cell and pupates. The 
pupal stage lasts 23 to 26 days, the insect completing its development 
from the egg to the adult in about 55 days. 

After emerging from the pupae the adults spend the remainder of the 
season in the soil, coming out occasionally to feed. They spend the winter 
in hibernation about the margins of fields, on ditch banks and roadsides, 
coming forth as soon as the frost leaves the ground in the spring. There 
is no evidence of more than one brood each season. 

95 



Blister-beetles 

(e) BLISTER-BEETLES 

(Figs. 8, 9, 12 and 13, Plate VII, Page 23) 

In nearly all lists of insects attacking the sugar beet mention is made 
of several species of blister-beetles. The economic status of some of our 
common species is difficult to determine, as the larvae, by destroying 
grasshopper eggs, render a real service to agriculture, while the adult 
beetles damage certain crops by feeding upon their leaves. 

A powder made of the dried bodies of the adult beetles is used in 
the treatment of certain diseases and injuries. When applied to the flesh 
in a paste form blisters are produced. This led to the beetles being 
called blister-beetles. The powder made from the dried bodies of a 
European species is known in the commercial world as Spanish-fly. 

NATURE OF INJURY 

The injury to crops (which is the result of the feeding of the adult) 
is similar to that caused by other leaf-eating beetles. 

These beetles are strong fliers, often appearing in swarms on sugar 
beets, potatoes and other crops, where they feed most ravenously for a 
time. Disappearing as suddenly as they come, they leave only the riddled 
remains of the crop. 

At such times applications of poisons are of little avail because of 
the great numbers of beetles and because of their voracity. Only the 
promptest action and most thorough application of whatever remedies 
are employed against them will be effective. 

METHODS OF CONTROL 
Poison 

As already stated, the use of poison is seldom effective. If poison 
is used, 2 to 2\ pounds of Paris green or 4 to 5 pounds of dry arsenate of 
lead, or 8 to 10 pounds of arsenate of lead paste, should be used in the 
quantity of water necessary to spray one acre. This varies from 50 to 
100 or 125 gallons in the different types of sprayers. 
Mechanical Measures 

As the beetles are very active and readily put to flight, driving them 
from a field is often the most effective means of preventing losses. This 
can be done by several persons, armed with brush or small branches of 
of trees, driving the beetles ahead of them. Always work in one direc- 
tion, taking as wide a strip across the field as possible, and going with the 
wind. 

According to Dr. Chittenden*, a windrow of dry straw or hay placed 
along one side of the field can be burned after the beetles have been driven 
onto it, thus destroying them. 

When small areas or gardens are attacked the beetles can sometimes 
be knocked into pans containing a small quantity of water covered with 
a thin film of kerosene. This method 4s not suited to large fields. 

When the beetles are not very numerous they can be dispersed and 
serious damage prevented by using the cultivator equipped as suggested 
for scattering flea-beetles, i. e., with pieces of rope or strips of canvas 
attached to the frame so as to drag on the plants. 

*"A Brief Account of the Principal Insect Enemies of the Sugar Beet," Bulletin No. 43, Division ot 
Entomology, U. S. Department of Agriculture (1903). 

96 



Blister-beetles 

DESCRIPTION AND LIFE HISTORY 

The blister-beetles are especially interesting because of the feeding 
habits of their larvae and because of the fact that they pass through more 
stages in the course of their development than any of the other beetles 
discussed in this Bulletin. There are six stages, the egg, three larval, 
the pupal and the' adult. 

Mention has already been made of the fact that the larvae of some 
species feed upon grasshopper eggs. The seasonal history of these may 
be summarized as follows : 

The Egg 

The eggs, which are small and oval in form, are very delicate. They 
are deposited in loose clusters in holes in the ground which have been 
excavated by the female blister-beetle. After the eggs are laid they are 
covered with loose soil which the beetle scratches over them with her feet. 

The places chosen for egg laying are just those warm sunny spots 
chosen by the female grasshopper for the same purpose. Thus we see 
that the newly hatched blister-beetle finds an abundance of food close 
at hand when it emerges from the egg. 

The First Larval Stage 

When the larva escapes from the egg its head is large and the jaws 
are well developed. Its legs are comparatively long and the body slender. 

As soon as the body walls become hardened by exposure to the air 
the active larva starts in search of a grasshopper egg-pod. When one is 
found the larva gnaws its way into it and begins feeding upon the eggs. 

At the end of its first meal of uncooked omelet, which may last for 
three or four days, the larva spends the next few days resting, and about 
the eighth day after beginning to feed the first molt takes place and the 
.second larval stage begins. 

The Second Larval Stage 

In this stage the body is much more robust and the legs are much 
shorter than before. After feeding for about a week another molt takes 
place. 

The legs and mouth are now rudimentary and the body resembles 
that of the white grub. 

After about six or seven days the skin is once more shed and what is 
known as the ultimate stage of the second larva is begun. In this stage 
the larva feeds more voraciously. 

After a week of almost continuous feasting the larva leaves the re- 
mains of its repast and burrows a short distance into the soil, where a 
smooth cell is formed. 

Within this cell another change takes place. About the third or 
fourth day the skin splits over the head and is gradually worked backward 
but is not entirely shed. The mouth and legs are now quite rudimentary, 
being represented, by small tubercles. The skin becomes quite rigid and 
takes on an orange yellow color (Fig. 12, Plate VII, Page 23). This is 
the pseudopupa or coarctate larva. 

The winter is spent in this form. In the spring the hard coarctate 
larval skin is cast off and the third larval form appears. 

97 



Blister-beetles Grasshoppers 

The Third Larval Stage 

In this stage (Fig. 13, Plate VII, Page 23) the larva is robust of body, 
and while the mouth parts and legs are well developed, it does not appear 
to feed. 

After burrowing about in the soil for a time the third larva changes 
to the pupa. 

The Pupa 

The pupa is white at first, becoming darker as the time for the 
emergence of the adult approaches. The legs, wings and antennae are 
free, as in the pupa of the alkali-beetle. 

The pupal stage lasts from five to six days, when the adult beetle 
appears. 

The Adult 

The adult blister-beetles are slender, rather soft bodied insects. In 
fall they are common objects on the flower clusters of goldenrod and 
other plants. 

The black blister-beetle (Fig. 8, Plate VII, Page 23) feeds upon 
Russian thistle and goldenrod blossoms, as well as potatoes and other 
crops. 

The ash-gray blister-beetle (Fig. 9, Plate VII, Page 23) is quite 
common in alfalfa fields in Northern Colorado, where it feeds upon the 
leaves of the alfalfa. 

3. GRASSHOPPERS 

During the early seventies the rich prairie soils of western Minnesota 
attracted many homesteaders, so that by the summer of 1876 (which is 
known as one of the worst grasshopper years in the history of American 
agriculture), the vast expanse of these prairies was dotted with claim 
shanties, tree claims and green fields. 

The first of June of this memorable summer all crops gave promise of 
a bountiful harvest. Then vague rumors of great hordes of Rocky 
Mountain locusts, which were destroying crops to the southwest, caused 
much apprehension among the settlers, many of whom had spent their 
last dollar in the planting of their crops, fully expecting the harvest to be 
sufficient for their future needs. 

About June 20th great swarms of hoppers began flying over, coming 
from the northwest and always traveling to the southeast. At times the 
swarms were so large and the hoppers flew in such dense bodies that one 
could look directly toward the sun without hurting the eyes. The light 
was dimmed as though a thin cloud obscured the sun. 

The suspense of the homesteaders had almost reached the breaking 
point when the wind changed and the long dreaded thing happened. 
Suddenly, about ten o'clock in the forenoon of July 5th people were 
startled by a loud, rushing sound like that of an approaching storm. 
Upon going outside a sight long to be remembered met their eyes. 

From the sky, like huge snow flakes, millions of Rocky Mountain 
locusts were dropping to earth. This living shower lasted for about 
half an hour, when it ceased as suddenly as it began. 

98 



Grasshoppers 

The ground was literally covered with a seething, kicking mass of 
hoppers three to four deep. Gradually this struggling horde became 
quiet, resting in regularly arranged rows and layers. In this position 
they remained for about four hours, when the work of devastating the 
fields began. Their work was rapid and thorough and the destruction 
complete. 

The writer's father describes the work of these hoppers in a corn 
field as follows: 

"After having rested for about four hours those hoppers next to the 
corn stalks began to feed upon them near the ground. As this weakened 
them the stalks fell and were immediately attacked by other hoppers. 
Stalk after stalk fell .until about sundown, when feeding ceased for the day, 
less than a hundred stalks remained standing in a \\ acre field. When 
the hoppers left this field not a vestige of the crop remained excepting the 
stumps of the corn." 

Garden truck, with the exception of peas, was also completely de- 
stroyed. Root crops such as beets and turnips were eaten leaf and root. 
Where each plant stood only a hole in the ground remained. As they 
devoured these roots the ravenous hoppers fought for a place until their 
bodies and extended legs resembled a bundle of sticks set on end in a 
small bowl. 

The third day the hoppers rose and started in a southeasterly direc- 
tion. They disappeared as suddenly as they came, leaving only bare 
ground and disheartened farmers behind over an area one hundred miles 
square. 

Nothing more was seen of the hoppers until early August, when a 
second but smaller swarm settled on the cropless country covered by the 
earlier one. This second swarm found little but the prairie grasses to 
feed upon. However, this furnished sufficient food for them until they 
had honeycombed fields and prairie with their egg pods. 

The following spring the whole country was a hopping mass of young 
Rocky Mountain locusts. Then began the fight to destroy this growing 
army and save what crops had been sown. 

All the young hoppers traveled in one direction. Whichever way 
they started in the morning was the direction for the day. While they 
were still small, trenches were dug in front of them into which they fell 
and in which they were buried. 

The hopper dozer played its part in the fight against the young hop- 
pers as they became larger and more active. By constant fighting some 
crops were partially saved, at an enormous cost of time and hard work. 

About the first of June the hoppers, having acquired wings, took 
flight for parts unknown. 

With the exception of very local outbreaks, which have been quickly 
brought under control, the Rocky Mountain locust has never since ap- 
peared within the bounds of the vast territory devastated during 1875 to 
1877. In those parts of its range where it was most numerous during 
these years it is almost unknown at the present time. 

Thus one of the most destructive insects of the Western Hemisphere 
came, devastated vast areas of crops and passed on, never since to appear 
in anything like the same numbers in any part of its former range. 

99 



Grasshoppers 

While the Rocky Mountain locust has almost ceased to be a pest, 
there are several other species of grasshoppers which frequently occur in 
great numbers and do much damage to crops within restricted areas. 
Three of these species — the two-lined hopper, the differential hopper and 
the red-legged locust — are worthy of special mention. 

(a) TWO-LINED HOPPER 

(Figs. 9, 10 and 11, Plate IV, Page 17) 

The two-lined hopper, together with the two following species, often 
occurs in large numbers in the Great Plains area. 

It is easily distinguished from our other injurious species by the two 
light lines beginning at the eyes and extending along the back and meet- 
ing at the tip of the wings. 

The females, one of which is shown, natural size, in Figure 10, Plate 
IV, Page 17, are larger than the males. The color of both sexes is yellow- 
ish or tan color, with darker, almost black markings. Some of the males 
are much darker than the females, there being very little yellow visible 
on these dark individuals. However, the light lines mentioned above 
are always clearly discernible. 

(b) DIFFERENTIAL HOPPER 

(Figs. 12 and 13, Plate IV, Page 17) 

Many times the differential hopper outnumbers the preceding one. 
Since the passing of the Rocky Mountain locust it has been one of the 
principal injurious forms in the Great Plains area. 

This hopper occurs in two colors, with many intermediate shades. 
Figure 12, Plate IV, Page 17 represents a male of the light or yellow 
phase, while Figure 13, Plate IV represents the opposite color extreme. 

In size this hopper resembles its near relative, the two-lined hopper. 
However, in all its color variations, it can be distinguished from the two- 
lined hopper by the lack of the two pale lines on the back. 

(c) RED-LEGGED LOCUST 

(Figs. 14 and 15, Plate IV, Page 17) 

The red-legged locust may be taken as representative of a group of 
small or medium sized species which have in the past been responsible 
for widespread damage to crops. 

In general appearance and size the red-legged locust resembles the 
Rocky Mountain locust already referred to, the lesser migratory locust, 
and the California devastating locust. 

It is very difficult to give a popular description of this grasshopper 
that will make it possible for one not trained in entomology to distinguish 
it from the other three species mentioned in the preceding paragraph. 

Figure 14, Plate IV, Page 17 represents an average male, natural 
size. The females are somewhat larger. The color of this hopper is 
variable, being brownish, shaded with almost black in the darker indi- 
viduals. In the light individuals, the lighter portions are yellowish 
brown. 

The slender part of the hind legs is usually reddish, although in some 
specimens it is yellowish or even pale green. 

100 



Grasshoppers 

NATURE OF GRASSHOPPER INJURY 

Grasshoppers belong to that group of leaf-feeding insects which bite 
their food. The crops attacked are often completely defoliated, and in 
the case of root crops such as sugar beets, turnips and others the roots 
are often eaten as well. The crowns of sugar beets are often completely 
destroyed and as a consequence the beets soon die, as they cannot develop 
new leaves. 

Young alfalfa is often destroyed by grasshoppers, especially where 
the ripening of the grain used as a nurse crop forces them to seek other 
green food. 

When attacking oats, grasshoppers have the peculiar habit of gnaw- 
ing off the kernels, which they seldom if ever eat. 

When other food fails, shade trees and shrubs are attacked and 
stripped of their leaves. 

During recent years grasshopper injury has usually occurred near 
wild land or waste land about the borders of fields, roadsides, ditch banks 
and fence rows, which are favorite breeding grounds of all grasshoppers. 
With the passing of the Rocky Mountain locust the migration of large 
swarms of grasshoppers from long distances appears to be a thing of the 
past. 

METHODS OF CONTROL 
Kansas Mixture 

The most effective remedy employed in the control of grasshoppers 
is the poisoned bran mash known as "Kansas Mixture, " which is made of 
the following ingredients: 

Bran 25 lbs. 

Paris green 1 \ lbs. 

Molasses 2 qts. 

Lemons 5 

Water, about 3 gals. 

It will be noted that the formula for use against grasshoppers is 
slightly different from that given on page 39 for use against cutworms. 

How to Prepare the Mixture 

In preparing this mixture proceed in the following manner: Thor- 
oughly mix the bran and Paris green while dry until the whole has a uni- 
form greenish color. Take about two gallons of water and add to this 
the molasses and lemons after the latter have been finely ground, rind and 
all. Stir this mixture until the molasses is completely dissolved, then 
pour it over the bran and Paris green. Mix until evenly moistened, 
then add water a little at a time until the mash is just wet enough to stick 
together well but yet dry enough to crumble readily when being spread. 

When to Apply the Mixture 

Grasshoppers spend the night on weeds and other plants well up 
above the ground. Not until after the sun rises and they have become 
warmed do they become active and begin feeding. After their night's 
fast the hoppers are hungry, so that if the poisoned bran is scattered 
before they begin feeding in the morning the best results are secured. If 

101 



Grasshoppers 

the mixture is put out in the evening it loses much of its odor during the 
night and is less effective as a result. When put out after the hoppers 
have filled up in the morning they are less hungry and do not eat so freely 
of the bait as earlier in the morning. Then by the time they are ready 
for another meal the sun has dried it more or less, which makes it less 
appetizing. 

Also, apply the remedy in the early part of the season, while the 
hoppers are small. "It is the early bird that catches the worm. " Like- 
wise it is the early farmer that gets the hopper. 

How to Apply the Mixture 

The Kansas Mixture should be thinly broad-casted over the ground. 
The most satisfactory way is to sow it by hand, using the same motion 
as in sowing grain or grass seed by hand. Care should be exercised to 
prevent leaving large lumps in the spreading, as these are apt to be eaten 
by live stock or poultry and cause their death. The mixture made with 
quantities, according to the formula given, is sufficient to cover 4J to 5 
acres. If thinly and evenly applied to this area there is no danger of 
either live stock or poultry being killed by feeding on treated land. 

Where to Apply the Mixture 

The poisoned mash should be scattered on waste land, borders of 
fields or other places where the hoppers congregate for the night. 

The Hopper Dozer 

During the years 1875 to 1877 many devices for destroying grass- 
hoppers, especially the wingless, young hoppers, were invented and cov- 
ered by patent rights. The inventors of some attempted to use sulphur 
fumes to kill the hoppers, others crushed them between rollers, and still 
others used the principle of the vacuum cleaner to suck the hoppers into 
their machine. 







Fig. 15. Hopper Dozer (After Chas. R. Jones, Bulletin No. 233, Colorado Agricultural 

Experiment Station) 

102 



Grasshoppers 

Of this assortment of mechanical hopper killers only the hopper 
dozer (Fig. 15, Page 102), as we know it today, has survived. This de- 
vice has long been recognized as effective in destroying grasshoppers, but 
its usefulness is confined to low standing crops, mown meadows, stubble 
fields and relatively flat ground. Where the ground is rolling or hilly the 
"live hopper machine" takes the place of the dozer. 

The hopper dozer consists of a sheet-iron pan about 4 inches deep 
and 12 to 16 feet long by 2| to 3 feet wide. This is separated into com- 
partments by cross partitions, making the compartments about square. 
These cross partitions are to prevent the liquid used in the pan from run- 
ning to either end when the dozer is used on slightly rolling ground. This 
pan is placed on runners made of 2x4 or 2x6 lumber. At the back and 
ends of the pan is an upright sheet of tin or oilcloth 2| or 3 feet high, 
against which the hoppers fly and are knocked or slide down into the pan. 

When in operation the pan is partially filled with water covered 
with a thin film of kerosene. As the hoppers accumulate in this liquid 
they are skimmed off. If this is not done the falling insects are prevented 
from becoming coated with the oil and water, which is necessary in order 
to kill them. The dozer is drawn by horses, one hitched at either end. 

A dozer of this sort can be built on the farm, and should be constructed 
for $6.00 to $7.00 when normal prices prevail. 

The Live Hopper Machine 

This device, which is of more recent origin than the dozer, is espec- 
ially adapted to use on rolling or hilly land where those devices which 
employ liquids cannot be satisfactorily worked. 

The live hopper machine consists of a box about 2 feet wide, 2 feet 
deep and 16 feet long, with bottom and ends of wood, and top and back of 
fine screen. The remaining side of the box is partially closed by a curved 
sheet iron or tin deflector about three feet high and extending along its 
entire length. The deflector reaches to within about three inches of the 
bottom of the box, the lower edge being curved backward into it. Just 
in front of this is a narrow strip of tin fastened to the bottom of the box 
directly under the bent-in portion of the deflector and curved outward 
and upward to a height of about six inches. Thus a curved mouth is 
produced along the entire length of the box. The hoppers flying against 
the deflector slide down into this mouth. The narrow strip of tin men- 
tioned prevents the hoppers from escaping by hopping off of the machine 
in front. Once in the mouth of the box, the light coming through the 
screen attracts them and the hoppers enter it in an attempt to escape, 
and are imprisoned. 

At each end of the box is a door which is used in removing the hop- 
pers from the machine after they have been killed by being sprayed with 
kerosene. 

The machine is placed on runners and drawn by horses in the same 
manner as the dozer. 

Harrowing and Discing 

Even though the hopper dozer is used and the Kansas Mixture ap- 
plied, many grasshoppers will reach maturity and many eggs will be laid 
each fall. In order fully to round out the season's work against the grass- 

103 



Grasshoppers 

hopper plague, all waste land should be thoroughly harrowed or disced. 
This harrowing and discing will break up the egg pods and scatter the 
eggs where exposure to the air and weather will destroy them. 

Many eggs will be deposited in alfalfa fields. The practice of reno- 
vating this crop with some one of the various makes of alfalfa renovators 
not only destroys many grasshopper eggs, but benefits the crop as well. 
Early spring or fall renovating is most effective in destroying grasshop- 
per eggs. 

Plowing 

Next to harrowing and disking, plowing egg infested land is one of 
the most effective cultural means of preventing hopper losses. Plowing 
alone does not destroy many of the eggs, but if the soil is plowed to a 
depth of four to five inches and the surface thoroughly worked with the 
harrow, a very small proportion of the young hoppers will succeed in 
making their way to the surface. 
Clean Culture 

Our injurious species of grasshoppers prefer weedy or grassy land as 
places to deposit their eggs. If all waste land about fields, ditches and 
fences is kept free of vegetation, few eggs will be deposited and adjoining 
fields will be comparatively free from injury. 

Poultry 

Poultry, if allowed to run at large, will rid considerable areas of 
grasshoppers. Turkeys are more valuable for this purpose then hens, as 
they range farther and spend more time in the fields. A small flock of 
turkeys is a double source of profit to the farmer. 

LIFE HISTORIES OF GRASSHOPPERS 

The life histories of our most injurious species of grasshoppers are 
very similar. 

The mature females usually select some dry sunny location covered 
with a growth of weeds or bunches of grass for depositing their eggs. The 
eggs are deposited in holes in the soil which are lined with a glue like 
substance secreted during egg laying. When this becomes hardened it 
protects the eggs from excessive drouth, moisture, and possibly to some 
extent, from predacious insects or egg parasites. 

In making these holes the female presses the tip of her abdomen, 
armed with four hard, curved and pointed plates (See Figs. 10 and 11, 
Plate IV, Page 17), against the soil. By alternately opening and closing 
these plates the soil is forced aside. 

When the hole is filled with eggs it is sealed with more of the glue- 
like secretion. This egg cluster inclosed within its impervious case is 
called an egg pod. Figure 8, Plate IV, Page 17 represents one of these 
egg pods removed from the soil. A portion of the covering has been re- 
moved near the upper end, exposing the eggs. The eggs are of a yellow- 
ish or olive yellow color, about one-fourth of an inch long, cylindrical, 
and slightly curved. Most females deposit two egg clusters, the total 
number of eggs laid varying from 50 to 100 or more. 

All of our injurious grasshoppers pass the winter in the egg stage. 
There are several species, however, that hatch in the fall and hibernate 
in an immature state, completing their development the next summer. 

104 



Grasshoppers 

Their presence about fields during warm weather in winter is responsible 
for many reports of early hatching of grasshopper eggs. 

Hatching begins during late May and early June and extends over a 
considerable period of time. Those eggs deposited on sunny, south 
slopes and in other protected locations hatch first. 

The young grasshoppers or nymphs (Fig. 9, Plate IV, Page 17) re- 
semble the adults but lack the wings of the latter. During their develop- 
ment they shed their skins several times. With each molt they resemble 
the adults more closely. Just before the last molt they appear as shown 
in Figure 1, Plate V, Page 19. At this time the wings are represented 
by four pads on the back of the insect. 

During the process of molting, grasshoppers cling to some plant to 
which the cast skin often remains fastened for some time. 

With the last molt the grasshopper becomes an adult with fully de- 
veloped wings. Mating soon takes place and egg deposition begins, 
usually, about the middle of August and continues until cold weather 
kills the grasshoppers. 

NATURAL ENEMIES 
Flesh Flies 

The larvae of several species of flies belonging to a family popularly 
known as "flesh flies" are parasitic upon grasshoppers. 

Figure 3, Plate IV, Page 17 represents a flesh fly 7 which was 
reared from the two-lined hopper. The larva or maggot of this fly is 
shown in Figure 4, Plate IV. 

The flesh flies here referred to are viviparous, which is to say that 
they give birth to living maggots instead of laying eggs. 

Mr. E. O. G. Kelley* describes the manner in which one of these 
flies places its larvae upon the host hopper substantially as follows : 

While the hoppers are on the wing the female flesh flies strike them 
on the under side of the lower wing, at the same time depositing a tiny 
maggot near its margin. When struck the hopper drops to the ground. 
The maggots were observed by this author to crawl along the margin of 
the wing to its base and then to enter the hopper's body through some 
natural opening or tender tissue. Once within the hooper the maggots 
feed upon its body fluids until mature. The hoppers usually live until 
the maggots are nearly full grown. However, these parasitized hoppers 
are apt to be sluggish and inactive several days before their vitals are 
destroyed and they die. When mature the maggots leave the dead 
hopper, burrow into the ground or conceal themselves underneath trash, 
change to pupae and later into adult flies. 

The flesh flies are foremost in the list of insect enemies of the grass- 
hopper and are of the greatest value to agriculture. They seldom appear 
in buildings in numbers, being denizens of the fields where their good 
work is done. 

Ground Beetles 

Several species of beetles commonly known as ground beetles (See 
page 130) are known to feed upon grasshopper eggs as well as the grass- 
hoppers, especially in their immature stages. 

*"A New Sarcophagid Parasite of Grasshoppers." Journal of Agricultural Research, Vol. II, No. 6 
(1914). 

( 7 ) See explanation of "Reference Figures." page 2. 

105 



Grasshoppers 

The egg-eating Amara (Figs. 20, 21 and 22, Plate IX, Page 27) be- 
longs to this family and is of especial interest because of the good work 
its larvae did in destroying eggs of the Rocky Mountain locust in the 
territories overrun by this insect in 1876 and 1877. 

Wherever grass- 
hopper eggs are plen- 
tiful, the larvae (Fig. 

20, Plate IX, Page 
27) of this beetle will 
be found. These 
whitish yellow grubs 
with brown heads 
and dark shields on 
each segment of the 
body burrow among 
the roots of grasses 
(Fig. 16, Page 106), 
where the female 
grasshoppers have 
deposited their eggs, 
and destroy them in 
large numbers. 

The change from 
larva to pupa (Fig. 

21, Plate IX, Page 
27) takes place dur- 
ing early May and 
the adult beetles 
(Fig. 22, Plate IX, 
Page 27) emerge two 
or three weeks later. 

Blister-beetles 

The part which the larvae of blister-beetles play in the destruction 
of grasshopper eggs has been discussed on page 96. However, the good 
work of these larvae is partially offset by the adult beetles feeding upon 
crops. 

Locust Mites 

The locust mite (Figs. 1,2, 17 and 18, Plate V, Page 19) is one of the 
most interesting as well as important enemies of the grasshopper. This 
little creature, which is closely related to the "chiggers" so common in 
some parts of the country, is not an insect but belongs to the same class 
of invertebrate animals as the spider. 

The animals of this class, which includes the scorpions, harvestmen, 
spiders, mites, ticks and others, .differ from the true insects in having four 
pairs of legs instead of three pairs in the adult stage and in having the 
head and thorax grown together. However, the immature stages often 
have but three pairs of legs. 

During those years when the Rocky Mountain locust overran the 
country west of the Mississippi river the ground was, at times, almost 
red with locust mites. 




Fig-. 16. 
Eggs 



Exposed Grass Roots, showing Grasshopper 
and Larvae of the Ground Beetle, Amara obesa 



106 



Grasshoppers 



The adult female (Fig. 17, Plate V, Page 19) deposits her eggs, a few 
of which are shown above the figure, in clusters of from 300 to 400. These 
are placed below the surface of the soil, often to a depth of \\ to 2 inches. 
The adult male, which is smaller than the female, is shown in Figure 18, 
Plate V, Page 19. 

In due time the minute, orange-red larvae, one of which is shown 
much enlarged in Figure 2, Plate V, Page 19, emerge. These larvae 
possess but three pairs of legs. However, they are very active and soon 
become attached to a grasshopper as shown in Figure 1, Plate V, Page 
19. Usually the young mites are found under the wing pads when there 
are but a few on an individual. 

These mites are sometimes mistaken for the red eggs of some parasite. 

The bodies of the young locust mites become distended in true tick 
fashion after feeding on a grasshopper and drop to the ground, moving 
about with difficulty in this condition. After secluding themselves 
under trash or among the clods on the surface of the soil the change to the 
pupa and from the pupa to the adult takes place. The adults, which 
feed upon the eggs of grasshoppers, spend the winter secluded beneath 
any object which furnishes protection from the weather. 

Hair Worms 

The hair worms or hair 
snakes (Fig. 17, Page 107, 




Fig. 18, Page 
16, Plate IV, 
still believed 
be animated 



08, and Fig. 

Page 17) are 

by some to 

horse hairs. 



Even those knowing the fal- 
lacy of this old belief do not 
always know the relation of 
these worms to other living 
creatures. The majority of 
those hair or "Gordian 
worms" observed swimming 
about in stagnant pools or 
the margins of streams and 
in irrigation ditches belong 
to the genus Gordius. 

The worms of this group 
are parasitic within insects. 
The eggs are laid in water, 
usually in the spring, and in 
the course of a week or ten 
days the young worms 
emerge. They are armed 

Fig. 17. Hair "Worm escaping from a parasitized w ith riiprrincr mrvnfl-i narfc 
Ground Beetle w , P lcI( - ln & mouul P<*ru> 

with which they force their 
way into the body of some insect where they become encysted in its 
muscles. This insect is in turn eaten by some other within which the 
encysted hair worm completes its development. Many Rocky Mountain 
locusts were destroyed by these worms during the outbreak of this insect 

107 



Grasshoppers 

in the seventies. Infested grasshoppers have a pale, sickly appearance 
and are more or less sluggish in their movements. 

Ground beetles are also often infested. Figure 17, Page 107 shows 
a common species just as the hair worm is emerging. Figure 18, Page 
108 shows the worm after freeing itself from the beetle. Figure 16, 

Plate IV, Page 17 repre- 
sents a mature male hair 
worm taken from a ground 
beetle. 

Birds 

A discussion of the natural 
enemies of the grasshopper 
would not be complete with- 
out mention of some of the 
many birds which assist in 
holding this pest in check. 

The list, of birds which 
render a real service to agri- 
culture by destroying grass- 
hoppers includes some which 
are not in very good stand- 
ing because of occasional 
damage to crops or raids 
upon the poultry yard or 
orchard, and because of a 
lack of knowledge of their 
feeding habits throughout 
the entire year. 

Generally speaking, all owls are looked upon as undesirables and 
as the legitimate prey of the hunter. As a matter of fact, with the 
exception of the great horned owl, these birds do far more good than 
harm. The occasional young chicken or turkey which they steal is small 
pay for the many mice, ground squirrels and other injurious rodents 
which they kill, to say nothing of the grasshoppers which some destroy. 

The long-legged burrowing-owl, which inhabits deserted prairie dog 
burrows, feeds very largely upon grasshoppers during those months when 
these insects are plentiful. As individuals they are among the most 
effective feathered grasshopper destroyers. 

While blackbirds are not so effective as individuals, their great 
numbers make them of even greater value than the burrowing-owls. 

The red-headed woodpecker is quite generally condemned for peck- 
ing holes in buildings, eating fruit and occasionally damaging other crops. 
Despite his bad habits, this bird is not without good points. Over 
seventy different kinds of insects enter into this bird's bill-of-fare, which 
includes many crop pests, among them large numbers of grasshoppers. 

Together with the owls, hawks enjoy a bad reputation among rural 
communities. It has been stated that of over seventy species of hawks 

108 




Fig. 18. The Hair Worm shmn in Figure 17, 
after it had escaped from the Beetle 



Grasshoppers 



Field Crickets 



and owls found in the United States but six are considered really injurious. 
These are the gyrfalcon, duck hawk, sharp-shinned hawk, Cooper's hawk, 
goshawk and great horned owl. 

The little sparrow hawk and the large, dark brown Swainson's hawk 
are noted insect eaters. Both of these feed freely upon grasshoppers. 

Fungous Diseases 

During late sum- 
mer numbers of 
dead grasshoppers 
are always observed 
clinging to weeds 
and other plants 
along the roadside 
or field border.- 
These have been 
killed by a fungous 
disease (Empusa 
grylliFves.). Grass- 
hoppers attacked 
by this disease 
climb to the top of 
some plant when 
about to die and 
clasp it with their 
fore legs. (Fig. 19, 
Page 109). In this 
position they die 
and remain clinging 
until their bodies 
become so decom- 
posed that they 
fall to the ground. 
This seems to be 
the most common 
disease attacking 
grasshoppers. 
However, there are 
several other fun- 
gous as well as bacterial diseases which destroy some grasshoppers 
nearly every year. 

4. FIELD CRICKETS 

(Fig. 7, Plate IV, Page 17) 

Crickets are familiar objects during late summer and early fall. 
Their lively chirping during mild fall evenings seems to add to the general 
spirit of harvest cheer. Yet these dusky cousins of the grasshopper are 
not without their bad habits. In fact, they are noted for their appetites 
and their liking for such articles as binder twine, clothes, carpets and 

109 




Fig. 19. 



Grasshoppers killed by the Fungous Disease, 
Empusa grylli 



Field Crickets 
Leaf-miners Beet or Spinach Leaf -miner 

rugs. Sugar beets are also sometimes attacked. The leaf stems are 
often eaten and deep pits are eaten in the crowns of the beets. Figure 7, 
Plate IV, Page 17 represents an immature female field cricket. 

5. LEAF-MINERS 

Thus far in our discussion of leaf feeding insects only those which 
feed exposed on the surface of the leaves have been considered. There is 
another group of leaf feeders, however, which live protected within gal- 
leries, or "mines," as they are popularly called, which result from the 
eating away of the pulp of the leaves while the outer portion or epidermis 
is left untouched. Some of these mines are serpentine in form, while 
others are irregular in shape, becoming unsightly and discolored as the 
season advances. 

Several species of leaf-miners are known to attack sugar and garden 
beets and mangels. However, only the following species appears to do 
any considerable damage to the sugar beet crop. 

(a) BEET OR SPINACH LEAF-MINER 

(Figs. 1, 2, 3, 4 and 5, Plate III, Page 15) 
NATURE OF INJURY 

The beet leaf-miners burrow into leaves and feed upon the pulp. 
At first the mines appear as tortuous whitish or brownish lines on the 
blade of the leaf. As the miners increase in size the mines become la v ge, 
irregular areas, as shown in Figure 1, Plate III, Page 15. 

While still inhabited the mines may have a watery appearance, 
and in case the greater part of a small leaf is mined out the leaf droops 
and appears to be decaying. If such leaves are held between the ob- 
server and a strong light the miner can be seen within, usually near the 
side of the mine. 

If the weather is very warm, dry beet leaves may wilt and lie on the 
hot soil during very warm days. Sometimes portions of these leaves are 
killed by the heat. These dead areas often appear very similar to the 
deserted mines of leaf-miners. They can be distinguished from them 
very easily, however, by the fact that the pulp still remains, there being 
no cavity between the upper and lower surfaces of the leaves. 

Ordinarily the damage to sugar beets is so slight that no account 
need be made of it. Occasionally, however, the miners are so numerous 
that they materially injure a crop. The destruction of the inner portion 
of the leaves has the same effect as though the entire leaf were destroyed. 

METHODS OF CONTROL 

It is doubly fortunate that the injury is usually so slight that reme- 
dial measures are not required, as there is no known remedy practical 
for field use. Several poisons have been tried, but all have proved un- 
satisfactory. 

Picking Infested Leaves 

In the case of small gardens the infested leaves can be picked off 
and destroyed. This will prevent the rapid multiplication of the miners. 

MO 



Beet or Spinach Leaf-miner Aphids or Plant-lice 

Clean Culture 

As in the case of many other insect pests, preventive measures are 
of more value than curative ones. The beet leaf-miner feeds in the leaves 
of lamb's-quarters, or white pigweed, as it is sometimes called. The 
destruction of this weed will do much to reduce the number of miners 
in a vicinity. 

DESCRIPTION AND LIFE HISTORY 
The Egg 

The eggs, which are placed on the under side of the leaves of the 
host plants, are shown natural size in Figure 1 "A," Plate III, Page 15. 
Usually they are laid side by side in groups of from two to five or six. 
Their surfaces are finely reticulated. Figure 2, Plate III, Page 15 repre- 
sents three eggs much enlarged, showing this reticulation of the surface. 

The Miner 

The miner (Fig. 3, Plate III, Page 15) hatches in about four days. 
It is a whitish maggot, pointed at the head and broadening toward the 
opposite end. When fully grown it is about one-fourth of an inch long. 
As soon as hatched it burrows into a leaf and begins to feed upon the 
pulp. 

The Pupa 

At the end of seven or eight days the fully grown miners drop to the 
ground and after burying themselves just below the surface or beneath 
trash lying on it, they pass into the pupal stage within the puparium 
(Fig. 4, Plate III, Page 15). The pupal state lasts from ten to twenty 
days during warm seasons of the year. The last generation of miners in 
the fall is thought to pass the winter in the pupal stage, the flies emerging 
the next spring. 

The Adult 

The adult miner (Fig. 5, Plate III, Page 15) is a two-winged fly 
belonging to the same order as the common house fly. This fly has no 
very distinctive markings. The face is silvery white between the eyes, 
which are brownish. The body, which is dull grey, is sparsely covered 
with quite long stiff hairs. 

B. SUCKING LEAF FEEDERS 

(Aphids or Plant-lice, True Bugs, Leaf-hoppers) 

1. APHIDS OR PLANT-LICE 

Aphids, or plant-lice, as they are commonly called, are small, soft- 
bodied creatures which usually feed in compact masses on the stems, 
leaves or roots of plants. Some feed exposed upon the plant (Fig. 20, 
Page 112), others cause the leaves upon which they feed to curl over them 
(Fig. 21, Page 1 12), and still others, like the sugar beet root-louse, spend 
a part of the season, at least, within galls produced by their feeding upon 
the host plant (Fig. 22, Page 113). 

Ill 



Aphids or Plant-lice 




Fig. 20. An exposed Colony of Plant-lice on a common roadside Weed 




Fig. 21. Leaves of White Ash curled by a Plant-louse 
112 



Aphids or Plant-lice 




Fig. 23. A common Wingless Aphid; Honey Tubes at "A' 1 
113 



Aphids or Plant-lice 

NATURE OF INJURY 

The indications of aphid infestation are varied, the different plant- 
lice affecting their hosts differently. A slow growth associated with 
wilting of the leaves, which are apt to be a pale yellowish green, is char- 
acteristic of root-louse attack. 

Most lice which feed above ground prefer the new, soft growth of 
plants. If the leaves and new growth wilt, if the leaves are covered with 
a sticky, sweetish substance called "honey dew," or if they become curled 
and distorted, plant-lice are very likely present. 

Ants are very fond of honey dew and in order to secure it are known 
to care for aphids and their eggs, exhibiting in this an instinct which 
amounts almost to reasoning. Ants and aphids are so closely associated 
that the presence of the former on a plant is a very good indication that 
the latter are present also. 

METHODS OF CONTROL 

The stomach poisons used in the control of biting insects 
will not kill plant-lice. Contact poisons must be used. Even 
then, the control of those aphids which live within galls or curled leaves 
is very difficult unless the remedy is applied during the season when the 
lice are in the egg stage or just as the eggs begin to hatch in the spring. 
After these lice once become inclosed within the galls or leaves it is impos- 
sible to reach them with any contact spray. Several species are so cov- 
ered with a fiocculent secretion that a spray must be very thoroughly 
applied and with considerable force to be effective. 

Kerosene Emulsion 

Where only a few plants in the garden or a small number of orna- 
mental shrubs are to be treated, kerosene emulsion has long been a stand- 
ard remedy because of its simplicity and the fact that all the ingredients 
required in its making are always at hand. 

This contact poison is usually made in the form of a stock solution, 
in which form it can be kept for several weeks. When used it is diluted 
by adding water. The s,tock solution is made as follows: 

Mix one-half pound of common laundry soap or whale oil soap in 
one gallon of water by boiling over a slow fire until the soap is completely 
dissolved. After removing from the fire add two gallons of kerosene and 
beat until the oil is thoroughly mixed with the soap and water. 

This stock solution is too strong for any plant and will kill the leaves 
and tender parts if applied to them. Before using thoroughly mix one 
part of the stock solution with ten to fifteen parts of water. Apply a 
little to the plants to be treated and watch the results. If the leaves 
are burned dilute the solution still more. 

Black Leaf 40 

This is a tobacco preparation containing 40 per cent nicotine, or the 
active poison in tobacco. As a remedy for plant-lice one part of "black 
leaf 40" is mixed with 600 to 800 parts of water and sprayed on the in- 
fested plants, care being taken to spray the aphids thoroughly. As the 
black leaf is very poisonous great care should be taken in handling it. 

114 



Aphids or Plant-lice 

Lime-sulphur Mixture 

In the case of those aphids which cause the leaves to curl, spraying in 
winter or early spring to kill the eggs and newly hatched lice is most 
effective. For this purpose the lime-sulphur mixture has proved satis- 
factory. This mixture may be made on the farm, but it can be pur- 
chased in a concentrated form from insecticide dealers at a cost not 
exceeding that of making it. The trees or shrubs to be treated should 
be thoroughly sprayed before the buds begin to open. 

Tobacco Decoction 

This is made by boiling tobacco stems or powder in water. Two 
pounds of the former to four gallons of the latter make a mixture suffi- 
ciently strong for general use. Do not let the mixture boil violently as 
this drives off some of the nicotine, thus reducing its strength. 

DESCRIPTION AND LIFE HISTORY 

In size and color the plant-lice vary greatly. Among the larger 
species the bright red Macrosiphum so common on the stems of golden- 
glow in late summer is very conspicuous. Contrasted with this is the 
small green species commonly found on the under side of rose leaves and 
clustered about the unopened buds. 

Many aphids have two tubes near the tip of the abdomen (Fig. 23, 
Page 1 13). These are called honey tubes, and it was originally supposed 
that the sweetish liquid or honey dew which is discharged from the ali- 
mentary canal was discharged through them. 

The mode of reproduction of plant-lice differs from that of other 
insects. The louse hatching from the over-winter egg and all of the 
individuals of several subsequent generations produce living young with- 
out the aid of the male element. This "asexual" reproduction, as it is 
called, usually continues until cold weather approaches. In the fall 
true males and females are produced. These mate and the females 
produce the eggs which carry the species over winter. 

In some species the young of a single individual consist of both males 
and females, while in the case of others one set of females bear all female 
and another all male young. 

The rate of reproduction is exceedingly rapid, a generation being 
produced every few days during warm weather. This rapid multiplica- 
tion results in widespread damage, many times, before the presence of 
the lice becomes known. 

NATURAL ENEMIES 

Were it not for the natural enemies of plant-lice in the form of pre- 
dacious and parasitic insects, fields, orchards and gardens would soon be 
overrun by them. 

Chief among these natural enemies are the lady-beetles, two of which 
are shown in Figure 10, Plate II, Page 13, and Figure 15, Plate IX, Page 
27, and their larvae in Figure 15, Plate II, Page 13, and Figure 23, Plate 
IX, Page 27. 

115 



Aphids or Plant-lice Green Peach-aphis 

The aphis-lion (Fig. 18, Plate IX) and its parent (Fig. 19, Plate IX), 
the lace-winged fly, are persistent aphid destroyers. (See pages 133 
and 134.) 

The larvae of many Syrphus-flies, one of which is shown in Figure 13, 
Plate VI, Page 21, devour large numbers of plant-lice. 

(a) GREEN PEACH-APHIS 

(Figs. 2, 9 and 10, Plate VIII, Page 25) 

As a sugar beet pest the green peach-aphis is of little importance. 
However, under favorable conditions for its multiplication, it often 
occurs in considerable numbers on the under side of beet leaves. 

NATURE OF INJURY 

Injury to sugar beets is due to the withdrawing of the sap from the 
leaves by the aphids in feeding. This retards the growth of the plants. 
The presence of lice is sometimes indicated by pale green or whitish 
blotches on the upper side of the leaves. 

As its name indicates, the green peach-aphis is found on the peach 
tree. It also feeds upon the plum tree. Its greatest damage is done to 
these trees during early summer. 

METHODS OF CONTROL 

Spray infested peach and plum trees with lime-sulphur mixture 
(See page 1 15) before the buds open in the spring to kill eggs and newly 
hatched stem-mothers. After the buds open use black leaf 40. (See 
page 114). 

The lice should be killed on the fruit trees. After they have mi- 
grated to the beets it is practically impossible to kill them. 

DESCRIPTION 

The apterous or wingless lice (Fig. 9, Plate VIII, Page 25) are most 
plentiful. A few winged lice (Fig. 10, Plate VIII, Page 25) may be found 
among the wingless ones, especially during the latter part of the sum- 
mer. These differ from the wingless individuals in coloring as well as 
form. The most distinguishing mark is the dark patch on the abdomen. 

LIFE HISTORY 

In early spring the eggs, which are deposited on peach or plum 
trees, hatch. In a few days the pinkish stem-mother, as the louse from 
the egg is called, becomes mature and begins depositing her young on the 
leaves. These young are not pink like their mother, but green, as shown 
in Figure 9, Plate VIII, Page 25. In due time these green lice begin 
giving birth to young. 

The lice of this third generation very largely become winged (Fig. 10, 
Plate VIII, Page 25). These winged lice migrate to a number of annual 
plants where the summer generations are produced. The list of about 
eighty plants upon which this louse spends the summer includes nearly 
every vegetable grown in the garden. 

116 



Green Peach-aphis Black Beet-seed Louse 

With the approach of fall the winged lice of the late summer gen- 
erations return to the peach and plum trees. The first lice to return to 
these trees give birth to wingless females which lay eggs instead of giving 
birth to young. About the time these females are mature the winged 
males begin to arrive from the summer hosts. 

After mating the females deposit several greenish eggs, which later 
become shining black. These eggs (Fig. 2, Plate VIII, Page 25) serve 
to carry the species through the winter. 

(b) BLACK BEET-SEED LOUSE* 

(Figs. 6 and 7, Plate III, Page 15) 

The black beet-seed louse is notorious because of its injury to sugar 
beet seed, both in Europe and America. In this country it has been par- 
ticularly destructive in some of the western states where beet seed is being 
grown on a commercial scale. 

NATURE OF INJURY 

In feeding upon beet seed plants the lice congregate in compact masses 
at the tip of the growing seed branches. Their feeding so exhausts the 
sap that the plants make very slow growth and in severe cases the infested 
branches die. The yield of seed is very materially reduced as a result of 
attack by this louse. 

METHODS OF CONTROL 

Hand Picking 

In Europe all infested branches are collected and carried from the 
field, together with the lice, and destroyed. This method is hardly prac- 
ticable except in the case of cheap labor and selected breeding plants. 

Black Leaf 40 

Spraying infested plants with black leaf 40 (See page 114), one part 
to 600 to 800 parts of water, will destroy the lice and not affect the quality 
of the seed. 

Winter Spraying 

Spraying the winter host with lime-sulphur mixture (See page 115) 
to destroy the eggs before the buds open or with black leaf 40 (See page 
114) as the lice are hatching in spring is undoubtedly the most effective 
means of controlling this pest. 

Destruction of Summer Hosts 

When lice occur on wild plants during the summer these should be 
destroyed, together with the lice on them. The destruction of all wild 
host plants in the vicinity of beet seed fields, before they become infested, 
is to be recommended. 



"There is some evidence that there may be more than one species of black louse attacking beet 
seed in the United States. This Bulletin discusses but one, the species damaging beet seed in Northern 
Colorado. 

117 



Black Beet-seed Louse 



DESCRIPTION 

The black beet-seed louse occurs in three forms. 

1. Wingless Lice 

The majority of the 
lice during the warmer 
months are wingless. 
These wingless lice (Fig. 
6, Plate III, Page 15) 
are a very dark, dull 
green. As the name 
implies, they are so 
dark as to appear black, 
with the exception of 
the legs, which are 
yellowish. Some of the 
older individuals have 
several white tufts on 
the abdomen. 

2. Pupae 

As the season ad- 
vances many of the lice 
develop wing pads. 
These are the imma- 
ture "alate" or winged 
lice. These pupae, as 
they are sometimes 
called, also have the 
white tufts on the ab- 
domen. 

3. Winged Lice 

The color of the 
winged lice (Fig. 7, 
Plate III, Page 15) is 
similar to that of the 
wingless individuals 
except that the head 
and thorax (that part 
of the body just back of the head) are a shining black. The wings show 
rainbow colors when the light strikes them at the proper angle. 

LIFE HISTORY 

The life history of this louse is very similar to that of the green peach- 
aphis. 

The winter is spent in the egg stage on the twigs of a shrub variously 
|known in different parts of the country as spindle tree, burning bush, 
£waahoo, and strawberry bush (Fig. 24, Page 118). 

The first winged lice in the summer migrate to the summer hosts, 
which include beet seed and a variety of weeds and wild plants, poppies, 

118 




Fig. 24. 



A Branch of Euonymus Species, showing 
Star-shaped Fruit 



Black Beet-seed Louse 
True Bugs False Chinch Bug 

and several varieties of beans, especially the horse bean of Europe. In 
the fall the migrants return to the winter host, where the sexual forms 
mate and the eggs are produced. 

2. THE TRUE BUGS 

People who are not familiar with their classifications are apt to apply 
the word "bug" to all insects. However, strictly speaking, this name 
is only properly applied to those sucking insects belonging to the order 
Hemiptera. Many authors confine the term to individuals of the 
sub-order Heteroptera. Like most of the scientific names of insects, 
this one seems unnecessarily long and meaningless to the average reader. 
It is taken from two Greek words, "heteros," meaning diverse, and 
"petron," a wing, and was suggested by the peculiar form of the wing of 
these bugs. 

The common stink-bug so frequently encountered on raspberries 
and other small fruits and the notorious chinch bug of the grain fields of 
the Mississippi Valley are familiar representatives of this group. 

Several species attack the sugar beet, of which the false chinch bug 
is the most important in the arid West. 

(a) FALSE CHINCH BUG 

(Figs. 11 and 12, Plate VIII, Page 25) 

This insect has attracted quite widespread attention because of its 
damage to sugar beet seed. When very numerous it has been known 
seriously to injure commercial sugar beets also. 

NATURE OF INJURY 

In feeding, the false chinch bug congregates in compact masses upon 
a few plants. The juice of these plants is so rapidly exhausted that they 
wilt and become lifeless in a very short time. 

When attacking commercial beets the bugs congregate about the 
crowns of small plants, or on the leaves, which soon become wilted and 
dead. The growth of commercial beets is very much retarded and in 
extreme cases small beets are killed. 

The growing tips of the branches of seed beets are attacked. The 
sap of these is soon so exhausted that they droop and die. The yield of 
seed is very much reduced by the feeding of this pest. 

When the sap of one plant is exhausted the bugs move to others, 
and as they are strong fliers and voracious feeders they affect large areas 
in a short time. 

Fields of commercial beets near waste land overgrown with pepper- 
grass or shepherd's purse and other plants of the mustard family are 
quite apt to be attacked. 

The odor of the blossoms of seed beets seems to attract the false 
chinch bug, which usually appears in seed fields about the time the plants 
begin to bloom. Of course the proximity of infested land to seed fields 
increases the infestation, at least early in the season. 

119 



False Chinch Bug 

METHODS OF CONTROL 
Clean Culture 

In the control of the false chinch bug preventive measures give more 
satisfactory results than the application of any remedy yet devised. As 
has already been intimated, this insect breeds upon various wild plants, 
especially shepherd 's-purse and other closely related plants of the mus- 
tard family. By preventing these weeds from growing about fields, 
ditch banks and roadsides the multiplication of the false chinch bug in 
a vicinity will be materially checked. 

Burning 

The bugs probably spend the winter in hibernation beneath dead 
weeds and about the roots of grasses growing on waste land. If all un- 
plowed land is cleaned up during the winter and early spring by burning 
all dead vegetation the hibernating bugs will be destroyed. If straw 
is spread over the ground and burned the treatment is often more effec- 
tive. Many other injurious insects which spend the winter in hiberna- 
tion in the same locations as the false chinch bug will be destroyed at 
the same time. 

Hand Picking 

Hand picking under certain conditions will serve to prevent the 
insect from injuring a crop. In catching the bugs a wide-mouthed dish 
of some kind should be used. Place a small quantity of water in this to 
which a little kerosene has been added. By suddenly slapping the 
infested plants the bugs can be knocked into the water and kerosene. 
The latter soon kills them. When the dead bugs cover the surface of 
the liquid skim them off. Whether or not this method of control is 
practicable will depend upon the value of the crop and the labor required. 
It is doubtful if it will pay in the case of large fields. In order that it be 
most effective the work must be done during the early morning or 
cool days, as in bright sunny weather the bugs are so active that they 
scatter upon the approach of the worker, so that but a small proportion 
are caught. 

Sticky Shields 

Sticky shields* carried through the fields have been used with some 
success. The same question of crop and labor values makes this a doubt- 
ful method except for small plots of very valuable crops and crops grown 
for experimental purposes. 

Spraying 

Various sprays have been employed, with rather indifferent results. 
Mr. F. B. Milliken* reports the killing of this pest by spraying with 
whale oil soap, one pound of soap to five gallons of water. According to 

*F. B M ! Iken. "The False Chinch Bug and Measures for Controlling It," Farmers' Bulletin No. 
762. U. S. Department of Agriculture (1916). 

120 



False Chinch Bug 

this author the above is too strong for turnips and radishes, for which 
one pound of soap to ten gallons water should be used, adding one part 
of nicotine sulphate to 1000 parts of water. 

DESCRIPTION 

The Egg 

The eggs, which are deposited in crevices of the ground and upon 
certain plants, are very small, being about ^\ of an inch long by about 
one-fourth as wide at the greatest diameter. They are finely ribbed 
lengthwise. The color is pale yellowish white, taking on an orange tinge 
as the young bug develops within. 

The Nymph 

The nymphs are slightly reddish when first hatched, becoming grayer 
with age. When about half grown they appear as shown in Figure 11, 
Plate VIII, Page 25. 

The Adult 

The adult (Fig. 12, Plate VIII, Page 25) is about - x \ of an inch long. 
The color of the head, body and legs is brownish gray, with fine dark 
spots over the surface. These spots are especially prominent on the legs. 
The wings are whitish. The color of the body showing through them 
gives them a grayish appearance. 

LIFE HISTORY 

The number of broods produced annually will depend upon the 
latitude and general weather conditions prevailing. There are probably 
four or five in the latitude of Denver. 

According to the author already quoted,* the late fall and early 
spring broods deposit their eggs in cracks in the soil surface or in pul- 
verized soil. During the warmer months the eggs are thrust among 
the clustered parts of plants such as the flower heads of some weeds** 
and the glumes of the strong scented stink-grass or love-grass. 

When first hatched the young feed upon weeds almost exclusively, 
especially the shepherd 's-purse, peppergrass and pennycress. 

At maturity the adults scatter to other plants. It is at this time 
that beet seed fields become infested. 

The adults of the last generation in the fall spend the winter in 
hibernation. 

NATURAL ENEMIES 

Very little seems to be known of the natural enemies of this bug. 
The writer has observed many adults containing the maggots of a small 
two-winged fly. 

Many bugs were killed by a fungous disease in breeding cages, but 
no noticeable effect of this malady was observed in the field. 

*F. B. Milliken. "The False Chinch Bug and Measures for Controlling It."' Farmers' Bulletin No. 
762. U. S. Department of Agriculture (1916). 

** Gaillardia pukhella Foug. Mollugo verticillata L. 

121 



Tarnished Plant-bug 

(b) TARNISHED PLANT-BUG 

The tarnished plant-bug is one of the most common of the true 
bugs. It is found everywhere in North America from Mexico to Canada 
and feeds upon almost any plant, either cultivated or wild. This bug 
often attacks sugar beets. 

NATURE OF INJURY 

Only when tarnished plant bugs are abundant are there any visible 
effects of their feeding. During the latter part of the season, however, 
they often attack the young leaves at the center of the beet crown in 
such numbers that the tips of these leaves wilt and finally become brown 
and dry. Frequently the injured beets begin to make growth in the 
axil of the outer leaves. This gives the beet top a bushy appearance. 

METHODS OF CONTROL 

Sugar beets are rarely injured to the extent where remedial measures 
are profitably applied. 

Clean Culture 

Since the tarnished plant-bug spends the winter in hibernation 
under the trash about fields, ditch banks and fence rows and breeds on 
the weeds growing in these places during the early part of the season, 
cleaning up all waste land by burning during winter or early spring will 
destroy many of them. By preventing the weeds from growing about 
fields the bugs are not so apt to be attracted to them as when these wild 
plants are plentiful in and about them. 

Kerosene Emulsion 

In the case of small garden plots kerosene emulsion (Page 1 14) is 
probably the best remedy where the nature of the crop attacked is such 
that it can be used. 

Dr. F. H. Chittenden* states that where insecticides are used they 
should be applied early in the morning while the dew is still on the plants 
an4 the bugs are not very active. 

Hand Picking 

Hand picking may be resorted to where the areas covered by the 
attack are small. It is obvious that this method is not suited to large 
fields. 

DESCRIPTION 
The Egg 

The eggs, which are about ^ of an inch long, are oval, several times 
as long as thick and flared at one end so as to be somewhat bottle-shaped. 
The color is a pale yellow. 

The Nymph 

The nymphs pass through four stages in the course of their devel- 
opment. In the first stage they are about -^ of an inch in length and 
of a yellowish or yellowish green color. 

*"A Brief Account of the Principal Insect Enemies of the Sugar Beet," Bulletin No. 43, Division 
of Entomology. U. S. Department of Agriculture (1903). 

122 



Tarnished Plant-bug 
Leaf-hoppers Sugar Beet Leaf-hopper 

The second stage differs from the first in that the nymphs are about 
twice as large and have two pairs of dark spots on the thorax. 

These spots become more distinct in the third stage and the wings 
are represented by two small pads on the back margin of the thorax. 

In the fourth stage the wing pads reach nearly half way down the 
back and the four dark spots become quite prominent. 

The Adult 

The adults are nearly one quarter of an inch in length. The color 
ranges from a greenish to a brassy brown. The markings are quite 
variable. Some individuals are quite prominently marked with black, 
yellow and red, while others are much more modestly colored, greenish 
brown predominating. 

LIFE HISTORY 

The adults, as already mentioned, as well as some nymphs in the 
third and fourth stages, hibernate under any convenient trash or under 
stones, boards and leaves about fields and waste land. 

The adults emerge during the first warm days of spring, and egg- 
laying begins soon after emergence. Little seems to be known about 
the place where the eggs are deposited. In all probability, they are 
placed within the stems of the plants upon which the adults feed. In 
the latitude of Northern Colorado the eggs of the first generation are 
deposited about the last of April and early May. 

About a month is required for the development of a single generation. 
Therefore, there are probably two or three generations each season. 

The generations overlap to such an extent that nymphs of all stages 
and adults can be found feeding together during the entire summer. 

NATURAL ENEMIES 

Very little is known regarding the natural enemies of this insect. In 
all probability it is held in check by predacious and parasitic insects 
and fungous diseases similar to those attacking the false chinch bug. 

3. LEAF-HOPPERS 

With the exception of the aphids, leaf-hoppers probably exceed in 
number of individuals all other families of sucking insects attacking 
cultivated crops. 

Although most leaf-hoppers feed upon grasses, often occurring in 
meadows in such numbers that it has been estimated that from one- 
fourth to one-half of all the grass growing annually is destroyed by them, 
several species seriously damage field crops, vegetables, fruits and shrubs. 

The small cream colored rose leaf-hopper which causes the whitish 
blotches on the leaves of cultivated and wild roses is familiar to nearly 
every one and will serve as a typical example of this group of insects, 
several species of which attack the sugar beet. 

(a) SUGAR BEET LEAF-HOPPER 

(Figs. 5, 6 and 7, Plate VIII, Page 25) 

Few insects attacking the sugar beet cause as large annual losses as 
this minute leaf-hopper. Fortunately this pest has not appeared to any 

123 



Sugar Beet Leaf-hopper 

damaging extent in the territory in which The Great Western Sugar 
Company operates. 

Its association with the disease known as "curly-top," (Fig. 5, Plate 
VIII, Page 25),ormore locally as "blight," "western blight" or "whis- 
kered beets" (Fig. 7, Page 60), has long been known, but just how its 
feeding produces the malady is not so well known. 



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gag 

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Fig. 25. Sugar Beet showing characteristic Curling n{ Leaves caused by Curly-top 
(After Harry B. Shaw, Bulletin No. 181. U. S. Bureau of Plant Industry) 

NATURE OF INJURY 
Indications of Injury 

The symptoms of injury by this leaf-hopper are to be found upon all 
parts of the plant. The first to appear is usually an inward curling of the 
inner leaves. This is associated with a distortion and enlargement of the 
veins of the leaf (Fig. 5, Plate VIII, Page 25). In severe cases the veins 
are covered with nipple-like protuberances. As the disease advances 
the whole plant becomes affected. The leaves become badly crumpled 
(Fig. 25, Page 124), the stunted roots develop an abnormally large num- 
ber of fibrous rootlets from the root seams (Fig. 7, Page 60), and the 
root itself becomes darkened, especially where the rings of fibrovascular 
bundles show in cross sections (Fig. 26, Page 125). The crown of the 
beet will often be covered with a sweet gummy substance which exudes 
from the beet. 

How the Disease is Transmitted 

In some way not at present thoroughly understood, certain so called 
virulent leaf-hoppers have the power of producing curly-top in healthy 
beets. A single individual which possesses this power will infect a 
healthy plant if confined upon it for five minutes.* 

*E. D. Ball, "The Beet Leafhopper and the Curly-leaf Disease That It Transmits," Bulletin No. 155, 
Utah Agricultural College (1917). 

124 



Sugar Beet Leaf-hopper 

Normal individuals do not have the power to cause the disease. It 
has been demonstrated quite recently that before a sugar beet leaf-hopper 
can transmit curly-top it must itself become inoculated by feeding upon 
a diseased plant. 

There seem to be many points in common between the carrying of 
curly-top by these leaf-hoppers and the relation existing between certain 
mosquitoes and malaria fever transmission. The micro-organism which 
is now supposed to be the real cause of the disease must be taken up by 
the leaf-hoppers while feeding on a diseased plant and then transmitted 
to healthy plants during the process of feeding upon them. 




Fig. 26. Cross Section of Sugar Beet, showing Darkening of Rings caused by Curly-top 
(After C. O. Townsend, Bulletin No. 122, U. S. Bureau of Plant Industry) 

Investigations, the results of which have just been published,* 
emphasize the importance of clean culture as a possible means of con- 
trolling this insect. 

These investigations show that without a doubt the wild host plants 
of the beet leaf-hopper become diseased and that when fed upon by non- 
virulent leaf-hoppers, these insects become inoculated and can and do 
transmit the disease to healthy sugar beets. The plant experimented 
with was a common mallow. 

METHODS OF CONTROL 

There is very little to be said regarding the control of this insect. 
In fact there is no known method by which curly-top can be prevented. 

The practicing of clean culture and the working and burning over of 
all possible hibernating places is always to be recommended, but even 
this is not sufficient. Until more is known of the insect and its associa- 
tion with curly-top we cannot hope to be able satisfactorily to prevent 
the damage it causes. There are cases on record where early planting 
prevented injury. This does not seem to be a sure remedy in all locali- 
ties, however. 

*" Wild Vegetation as a Source of Curly-top Infections of Sugar Beets," Boniquit and Slake, Journal 
of Economic Entomology, Vol. 10, No. 4 (1917). 

125 



Sugar Beet Leaf-hopper Clover Leaf-hopper 

DESCRIPTION 
The Egg 

The eggs, which are pearly white, are deposited in the tender stems 
of beet leaves. Late in the season the elliptical scars caused by the 
punctures made in depositing the eggs are sometimes very numerous. 

The Nymph 

The young leaf-hoppers or nymphs (Fig. 6, Plate VIII, Page 25) are 
very minute, active little fellows of a creamy white color. They are so 
small and so easily disturbed that they are found only by making very 
careful search for them. 

The Adult 

The fully matured sugar beet leaf-hopper (Fig. 7, Plate VIII, Page 
25) is about one-eighth of an inch long, and with the exception of the eyes, 
is of a light creamy white color. They are so exceedingly small and active 
that they are very difficult to observe in the field except as they fly from 
plant to plant. 

LIFE HISTORY 

The following summary of the life history and habits is taken from 
U. S. Department of Agriculture Bulletin No. 181, by Harry B. Shaw: 

"The beet leaf-hopper is single brooded and begins to deposit its 
tiny, white eggs in the stems and midribs of beet leaves from about the 
end of June — the time doubtless varying somewhat with the locality and 
local climatic conditions — until the end of August. Probably the major- 
ity of the eggs are deposited by the middle of July. The nymphs begin 
to appear about the second week in July, and the writer has observed 
their appearance in considerable numbers in Idaho as late as the end of 
August. Slit-like scars are produced on the beet stems where the eggs 
have been deposited ; sometimes these ovipository scars are very numer- 
ous and conspicuous. The egg stage appears to last about fifteen days, 
and the young insects reach the adult stage in about twenty days more. 
These adults hibernate and resume their activity the following spring. 
In Utah and Idaho they have been seen on weeds in May and on beets 
near the end of May or early in June. The greater portion of the nymph 
stage appears to be spent among the inner leaves and petioles of the plant, 
where the egg is hatched, and as the insect approaches the adult stage it 
gradually works outward. 

"The beet leaf-hopper is an exceedingly active insect; its favorite 
mode of locomotion is by hops of lightning-like rapidity. The range of 
its leaps seems to be about 18 inches. The adult while on beets uses its 
wings but little. In common with several closely related species it is a 
true sucking insect; it is provided with powerful head parts and a stout 
bill. The latter when not in use is tucked snugly against the under side 
of the body." 

(b) CLOVER LEAF-HOPPER 

(Fig. 8, Plate VIII, Page 25) 

The clover leaf-hopper is frequently encountered in'quite large num- 
bers in beet fields and is often mistaken for the sugar beet leaf-hopper 
just discussed. It can be easily distinguished from it, however, by its 

126 






Clover Leaf-hopper 

more robust form, slightly larger size and darker color. The two dark 
spots on the head between the eyes serve to distinguish it from many 
other small, grayish species with which it is often associated in clover 
and alfalfa fields, where its greatest damage is done. 

NATURE OF INJURY 

Fields of sugar beets where this crop has followed alfalfa have been 
seriously damaged in the early part of the season while the beets were 
still small. The injury is most severe during dry, hot weather. 

The leaves of sugar beets attacked by this insect are covered with 
light, grayish areas as a result of the punctures and irritation caused in 
feeding. If the weather is dry and warm the plants show a very striking 
lack of thrift and make very slow growth. An examination of such beets 
will reveal the leaf-hoppers on the under side of the leaves, or during 
bright sunny days they will be seen flying ahead of one walking through 
the field. 

METHODS OF CONTROL 
Clean Culture 

Keeping waste land free of rubbish by burning all dead vegetation 
during the fall will prevent the adults from hibernating about fields. 
Burning during the winter or early spring will destroy the hibernating 
adults. 

DESCRIPTION 

The Egg 

The eggs, which are white and very small, are placed in slits in the 
host plants. These slits are made with the saw-like ovipositor of the 
female. 

The Nymph 

The young or nymphs resemble the adults in form but lack the wings 
of the latter. Their color is a creamy white with darker spots and bands. 

The Adult 

The adult leaf-hopper (Fig. 8, Plate VIII, Page 25) is of a light gray- 
ish color with dark markings. The face is marked with short, dark 
stripes and just between the eyes on the top of the head are two dark 
spots. 

LIFE HISTORY 

The hibernating female places her eggs in the stems of plants in early 
spring. These hatch in from five to twelve days during the warmer 
months. 

The number of generations varies with the latitude and general 
weather conditions. In the latitude of Denver there are at least two 
and probably three each year. 

The nymph stage lasts from 20 to 30 days, with an average of about 
25 days. The last generation hibernates during the winter at the base 
of clumps of grass and about the roots of weeds or under rubbish lying 
about fields and waste lands. 

127 



Clover Leaf-hopper Eutettix Strobi 

In the warmer sections of the Southern states the adults are more or 
less active during the entire year, and in the extreme South they do not 
hibernate at all. 

(c) EUTETTIX STROBI FITCH 

(Figs. 1, 3 and 4, Plate VIII, Page 25) 

This bright colored leaf-hopper (Fig. 4, Plate VIII, Page 25) is the 
cause of the deep purple blotches (Fig. 1, Plate VIII, Page 25) so often 
seen on the leaves of lamb's-quarters and sugar beets during spring and 
summer. 

It is not of interest to beet growers because of any damage it does 
to the crop but because of the widespread attention which the discolora- 
tion of the leaves, caused by its feeding, attracts. 

During late spring and early summer and again during late summer 
the nymphs (Fig. 3, Plate VIII, Page 25) may be found on the under 
side of the leaves, resting on the colored spots. Their color harmonizes 
so completely with these spots that they are easily overlooked. 

The adults (Fig. 4, Plate VIII, Page 25) are very prettily marked 
with shades of tan and brown, and measure about one-fourth of an inch 
in length. The dark saddle across the center of the wings is especially 
prominent. This is one of our most brightly colored and attractive 
leaf-hoppers. There appear to be two broods of this insect annually, 
the adults appearing in June and August. 



128 



Beneficial Insects 
CHAPTER IV 



BENEFICIAL INSECTS 

So much is written about the injurious insects in bulletins and farm 
papers that we are apt to look upon all insects as the arch-enemies of 
mankind. However, if we study those about us carefully we are soon 
astonished at the number of friends we have among them, friends whose 
whole existence is one constant warfare against our enemies. It is not 
enough that we learn to recognize enemies alone; we should know our 
friends as well and do all we can to encourage and protect them. 

In the preceding pages frequent mention has been made of beneficial 
insects in connection with the particular injurious species which they 
help to control. However, out of justice to our insect friends and our- 
selves it is only right that we devote a few pages to a general discussion 
of this large but little appreciated group. 

Every order of insects contains forms which feed upon other forms 
of insect life. However, these friendly species are in some cases so 
minute that they are overlooked, or their work of ridding our fields of 
noxious insects is carried on so quietly that their presence is not apparent. 
Still others so resemble some of the injurious species that their real mis- 
sion is not suspected. Instead they are blamed for the damage they are 
really helping to prevent. Many times friends are taken for foes because 
in searching for the real culprits they are forced to frequent the damaged 
crop. Unless we are familiar with these insects they often share the fate 
of the spy who, in order to hide his identity more completely, appears in 
the role of an enemy. 

Beneficial insects are spoken of as either predacious or parasitic. 
Owing to the fact that, in habits, these two groups are not clearly defined, 
but merge one into the other, it is very difficult to give a definition of 
the terms predacious and parasitic which is wholly satisfactory. 

In a general way insects which wander about in search of the insects 
upon which they feed are spoken of as being predacious. Insects of this 
class require many hosts or victims for their maintenance. 

Insects which pass the entire larval stage within the body of a single 
host, or attached to a single host from which they draw their nourish- 
ment, are said to be parasitic. 

Parasites gain entrance to the host in many ways. The adult para- 
site of some species stings its eggs into the body of the host, using for this 
purpose a sharp organ called the ovipositor. This is usually located at 
the tip of the abdomen or near it on the underside of the body. Other 
parasites fasten their eggs onto the surface of the host's body. When 
the young parasite emerges from the egg it burrows into the host. In 
other cases the young parasite remains on the outside with only a small 
portion of its body, including the head, buried in the host. 

The larvae of certain flies are deposited upon the host and immedi- 
ately proceed to enter its body through natural openings or by burrowing 
through some tender tissue. 

129 



Beneficial Insects 

These parasitic larvae feed upon the blood of the host insect. The 
host in many cases remains alive and functions naturally until the para- 
site is fully mature. In the case of some caterpillars the parasite does 
not emerge until after the change to the pupa has taken place. 

Some parasites live only within closely related insects. Thus certain 
kinds are parasitic upon cutworms only, others upon grasshoppers and 
related insects, and still others upon the eggs of certain insects. 

Since these parasites are dependent upon certain hosts for their 
existence their numbers rise and fall with the increase and decrease of 
their hosts. This is why some noxious insects become so numerous at 
times. A scarcity of these insects is followed by a scarcity of their para- 
sites. When the parasites become very few and favorable conditions 
exist for the multiplication of a particular insect it often increases so 
rapidly as to do much damage before the parasites again get the upper 
hand. 

A. PREDACIOUS INSECTS 

1. GROUND BEETLES 

(Figs. 1, 2, 3, 20, 21 and 22, Plate IX, Page 27) 

The popular name, "ground beetle," has been applied to these 
beetles because they are most frequently encountered running rapidly 
over the ground or lurking under stones or other objects lying on its surface. 

The majority of these beetles are shining black. However, some are 
bright metallic green, dark blue, brown or even spotted. Their legs are 
long and slender and their movements rapid. 

Most of the species are predacious, feeding upon other insects which 
they capture either by pouncing upon them or by chase. Several species 
feed upon vegetable matter, but their depredations are rarely, if ever, of 
great economic importance. 

The larvae of ground beetles frequent the same places as the adults, 
and, like them, are predacious. Figure 1, Plate IX, Page 27 will serve 
as a typical example of ground beetle larvae. Figure 3, Plate IX, Page 
27 represents a very common, black ground beetle, while Figures 20, 21 
and 22, Plate IX, Page 27 represent the larva, pupa and adult of a 
species already mentioned in connection with the natural control of 
grasshoppers. 

(a) FIERY HUNTER 
(Figs. 1 and 2, Plate IX, Page 27) 

The fiery hunter is one of our largest ground beetles and can be 
recognized by the copper colored or golden spots on the wing covers. 
This beetle (Fig. 2, Plate IX, Page 27) and its larva (Fig. 1, Plate IX, 
Page 27) are particularly fond of caterpillars. By some authors it is 
known as the "caterpillar killer." Many a cutworm has fallen a prey to 
these beetles. 

(b) BOMBARDIER-BEETLES 

The members of one group of ground beetles are provided with a 
sack of very volatile fluid at the tip of the abdomen. When pursued, 
this fluid is ejected with a loud popping sound and as it comes in contact 
with the air it is reduced to a gas which appears like a tiny puff of smoke. 
The sharp report accompanied by the puff of smoke-like gas suggested 
the name "bombardier-beetles," by which these beetles are known. 

130 



Beneficial Insects 

2. TIGER-BEETLES 

(Figs. 5, 6 and 7, Plate IX, Page 27) 



■■■■HBHBHBBI 



'- ~ . J~ 




Fig. 27. Entrance to Burrow of Tiger-beetle Larva. 
There is never any soil at the entrance to these bur- 
rows. 




Fig. 28. Same Burrow as shown in Figure 27, with 
head of larva resting on level with the surface, ready 
to seize a victim. 

131 



The tiger-beetles 
are common objects 
about the borders of 
fields or on beaten 
pathways and road- 
sides. They are lov- 
ers of sunshine and 
frequent exposed po- 
sitions. 

The tiger-beetles 
are the most agile 
of all beetles, being 
equally at home on 
the ground, where 
they run with amaz- 
ing rapidity, or on 
the wing. When ap- 
proached they take 
flight, fly a short dis- 
tance, and invaria- 
bly alight facing the 
intruder. 

The larvae and 
adults are preda- 
cious, feeding entire- 
ly upon other in- 
sects. One author 
states that the only 
thing in common be- 
tween these beetles 
and their young is 
their eagerness for 
prey. 

The larva (Fig. 
5, Plate IX, Page 
27) is an uncouth 
creature and spends 
its entire existence in 
a perpendicular bur- 
row (Fig. 27, Page 
131) in the hard 
ground of some path 
or roadside. During 
the day it lies with 
its head just at the 
surface of the ground 
(Fig. 28, Page 131), 
its jaws open like a 
steel trap, waiting 



Beneficial Insects 

for some unfortunate insect to pass near. When one comes within reach 
the jaws snap shut and the victim is drawn into the burrow and devoured. 

In order to prevent some stronger insect from dragging the young 
tiger-beetle from its burrow, nature has provided it with a peculiar anchor 
in the form of a hump on the fifth segment of its abdomen. This hump 
is armed with several curved hooks which fasten into the walls of the 
burrow, thus making it possible for the larva to withstand the pull of a 
powerful victim. 

The adults (Figs. 6 and 7, Plate IX, Page 27) are usually a metallic 
green or bronze banded with light markings, from which comes the name 
"tiger-beetle." However, some are black, while others are light, in har- 
mony with the color of the sand on which they live. 

3. LADY-BEETLES OR LADY-BUGS 

(Figs. 14, 15, 23 and 24, Plate IX, Page 27; Figs. 10 and 15, Plate II, Page 13; 
Fig. 14, Plate VII, Page 23) 

The lady-beetles, or lady-bugs, as they are commonly called, are 
among the best known and most important predacious insects. 

Both the adults and larvae feed upon small, soft bodied insects and 
insect eggs. 

These beetles have the peculiar habit of congregating in very large 
numbers in the fall of the year just before going into hibernation. At 
such times they can be scooped up by the quart as they cluster about the 
bases of trees and shrubs or under stones, in layers many deep. Such a 
congregation of the species discussed below occurred at the very top of 
one of the highest mountain peaks near the city of Denver in 1916. 

Hippodamia convergent (Fig. 15, Plate IX, Page 27) is the com- 
monest of all species. This, together with several others, is especially 
noted for the numbers of plant-lice which it destroys. The larva (Fig. 23, 
Plate IX, Page 27) is a common object among colonies of plant-lice, 
where the pupa (Fig. 24, Plate IX, Page 27) is also often encountered 
fastened to a twig or leaf. Other species are especially useful for their 
work in orchards, where they devour scale insects which would otherwise 
injure the trees and fruit. Figure 10, Plate II, Page 13 shows a lady- 
beetle which feeds upon sugar beet root-lice. Figure 15, Plate II, Page 
13 shows the larva, and Figure 14, Plate VII, Page 23, the pupa, of this 
same beetle. 

The eggs of lady-beetles vary with the species, as does the place 
selected for depositing them. Those of our common forms resemble 
the eggs of the Colorado potato-beetle, but are smaller. They are de- 
posited in clusters, the eggs standing on end. A cluster of the eggs of 
Hippodamia convergent is shown in Figure 14, Plate IX, Page 27. 

4. TRUE BUGS 

(Fig. 14, Plate II, Page 13) 

The majority of the true bugs are vegetable feeders, and pests of the 
first magnitude. However, several families contain species which are 
predacious, feeding upon the blood of other insects or the higher animals, 
which is sucked up through their strong, jointed beaks. 

132 



Beneficial Insects 

(a) ASSASSIN-BUGS 

The members of this family are so pre-eminently predacious that 
they are known as the assassin-bugs. Their mode of attack is truly that 
of the assassin. Approaching their prey by stealth or lying in wait for it, 
they pounce upon their victims and pierce them, oftentimes in the back, 
with their beaks and proceed to drink up their life blood. 

One noted member of this family feeds upon bedbugs and is known 
as the masked bedbug hunter. This insect infests houses where its prey is 

found. 

(b) AMBUSH-BUGS 

The bugs of this family are called ambush-bugs because of their 
habit of lying concealed in flowers, especially those of thistle and golden- 
rod, patiently waiting for some nectar loving insect to visit their ambush. 
The unlucky visitor is grasped with the much enlarged fore legs of the 
ambush-bug and impaled on its strong beak. 

The common species of this family are yellowish or greenish, marked 
with dark bands and spots. The abdomen is broadened behind, con- 
cave on top and very convex below. The forward pair of legs is very 
much enlarged and armed with heavy claws with which the bug's prey 

is held. 

(c) STINK-BUGS 

(Figs. 8 to 13, Plate IX, Page 27) 

The members of the stink-bug family are furnished with glands 
which secrete a very ill-smelling fluid which escapes through two open- 
ings on the under side of the body. 

While most of these bugs feed upon vegetables, some being noted 
pests, several species are predacious. 

The pictured soldier-bug (Figs. 12 and 13, Plate IX, Page 27) is noted 
as a destroyer of potato-beetles, and also feeds upon alkali-beetle larvae. 
The eggs (Fig. 8, Plate IX, Page 27, natural size, and Fig. 9, Plate IX, 
Page 27, enlarged) are placed on the leaves of potatoes and other plants 
where the insects fed upon by the young are found. 

When first hatched the young are reddish, as shown in Figure 11, 
Plate IX, Page 27. The half-grown nymphs appear as in Figure 10, 
Plate IX, Page 27. The adults are of two colors, as shown in the figures. 

5. LACE-WINGED FLIES 

(Figs. 16, 17, 18 and 19, Plate IX, Page 27) 

The delicate, green, lace-winged fly or golden-eyes (Fig. 19, Plate IX, 
Page 27), as it is frequently called, is a familiar object flitting about in 
the cool of dense foliage, especially where aphids or other small, soft 
bodied insects are numerous. 

The eggs (Fig. 16, Plate IX, Page 27) are always attached to the 
surface of a leaf or other object by a hair-like stalk about one-half inch 
long. One author* states that this is nature's way of protecting the 
unhatched eggs from the newly hatched larvae, which are so exceedingly 
voracious that even their own unhatched brothers and sisters are not 
safe when other food is not available. 

*Comstock. "Manual of Insects," page 181. 

133 



Beneficial Insects 

The larvae (Fig. 18, Plate IX, Page 27) are common among aphid 
colonies. When first hatched they devour these soft bodied insects at 
the rate of four or five a day and at the rate of twenty or more a day 
when fully grown. Because of the numbers of plant-lice they devour, 
these spindle-shaped larvae are called aphis-lions. 

In feeding, the aphis-lion seizes its prey in its long jaws, which are 
so formed that each pair makes a tube through which the body contents 
of the aphid are sucked up. 

During its existence as a larva the lace-winged fly probably con- 
sumes from 300 to 400 plant lice.* 

Many other small insects are eaten besides aphids. In the article 
referred to in the preceding paragraph, the author lists ten insects be- 
sides several species of plant-lice as hosts of the green lace-wing of Cali- 
fornia. Among these are mites, leaf-hoppers, scale insects, mealy-bugs 
and psyllids. 

When the larvae are fully grown they spin a white globular cocoon 
(Fig. 17, Plate IX, Page 27), within which the pupal stage is spent. The 
adult escapes by gnawing the end of the cocoon partially off and pushing 
this up as shown in the figure. 

As there are several generations of the lace-winged fly each season 
their importance as destroyers of injurious insects is difficult to estimate. 

6. WASPS 

(a) DIGGER-WASPS 

(Figs. 16, 17 and 18, Plate VI, Page 21) 

We are so accustomed to considering wasps as creatures of quickly 
aroused temper who resent any trespassing in the vicinity of their nests 
by stinging the intruder, that many an innocent and beneficial member 
of the wasp tribe is summarily put to death and as a result many a crop 
pest continues its work of devastation. 

There are fourteen families of digger-wasps in America north of 
Mexico. Many of the members of these render invaluable service to the 
farmer and gardener by destroying the insects feeding upon his crops. 
In habits many of these represent a class intermediate between the true 
predators, such as the ground beetles, and the true parasites, which will 
be discussed later. 

(a-1) FAMILY SCOLIIDAE 

One member of this family, Tiphia inornata, which has been pre- 
viously mentioned, burrows into the ground in search of white grubs, 
upon which it lays its eggs and upon which the larvae are parasitic. 

These wasps are shining black and about three-fifths of an inch long. 

(a-2) SPIDER-WASPS 

Most of the members of this family dig burrows in the ground which 
are stocked with spiders upon which the young wasps feed. A few spe- 
cies, however, build cells of mud which are fastened under stones and in 
other secluded places. 

(a-3) THREAD-WAISTED WASPS 

The wasps of this family can be distinguished from those of the pre- 
ceding ones by the long slender first segment of the body. The peculiar 

*V. L. Wildermuth, "California Green Lacewing Fly," Journal of£Agricukural Research. Vol. VI. 
No. 14 (1916). 

134 



Beneficial Insects 




Fig. 29. Nest of a Mud-dauber taken from Rafter of an Out-building 

development of this joint suggested the name "thread-waisted wasps" 
by which they are commonly known. 

Many of these species build large many celled nests of mud on the 
beams of outbuildings and about farm machinery stored under imple- 
ment sheds (Fig. 29, Page 135). 

The cells of these nests are provisioned with spiders and caterpillars, 
upon which the young wasps feed. 

After dry spells these wasps are common objects about mud puddles 
near wells or after showers, where they secure the mud required in the 
construction of their nests. 

(b) SOLITARY WASPS 

(Fig. 15. Plate VI, Page 20) 

These insects, many species of which resemble the fiery tempered 
yellow jackets, are peculiarly subject to persecution because of this 
resemblance. 

Some of the members of this family are masons, building their nests 
of mud; some are miners, digging tunnels in the earth in which their 
young pass through the stages of their development; and still others are 
carpenters, cutting out tubular nests in wood, and partitioning these off 
into cells with mud. 

One species (Fig. 15, Plate VI, Page 21) has already been mentioned 
in connection with the sugar beet webworm (Seepage 44), and its bur- 
row figured on page 78 (Fig. 14). 

Another species builds a jug-shaped nest, which is attached to the 
stem of some plant, and provisions it with small caterpillars. 

B. PARASITIC INSECTS 

While the predacious insects do much to keep down the enemies of 
cultivated crops their work is not so effective as that of the true parasites, 
such as the Ichneumon-flies, Braconids, and Chalcis-flies. 

135 



Beneficial Insects 



1. ICHNEUMON-FLIES 

(Fig. 5, Plate I, Page 1 1 ; Fig. 7, Plate V, Page 19; Figs. 9 and 10, Plate VI, Page 21) 

Many times when our fields are overrun by a pest we wish that by 
some magical power we could destroy it and save our crops. Sometimes 
these pests do disappear as if by magic. Many times we little suspect 
that the small to medium sized, wasp-like insects, which we observe hov- 
ering over the field, are the friends that stood by us in our hour of need 
and wiped out our enemies in an incredibly short time. 

The Ichneumon-flies belong to the same order of insects as the digger- 
wasps, already discussed. 

These flies have long slender bodies. That of the female is often 
armed with a long hair-like ovipositor (Fig 7, Plate V, Page 19). This 
is composed of three parts. The central one is a tube through which the 
eggs pass, while the two outer ones are the sheath which protects the 
ovipositor proper. When the insect is alive the three parts are held close 
together and appear as a single hair-like organ. 

The name "Ichneumon" was suggested by a fancied resemblance to 
the Ichneumon of Africa, which is a mammal belonging to the same 
family as the mink and weasel. 

Mention has already been made of two Ichneumon-flies. Figure 5, 
Plate I, Page 11 is parasitic upon caterpillars and was reared from the 
western army cutworm. Figures 9 and 10, Plate VI, Page 21 represent 
a species which destroys the alfalfa looper. 

2. BRACONIDS 

(Figs. 6 and 7, Plate ] Page 1 1 ; Fig. 14, Plate V, Page 19) 
Closely related to the Ichneumon-flies is a group known as the Bra- 
conids. The members of this family are small or minute insects. 

Frequently dead cater- 
pillars are observed cov- 
ered with small silken 
cocoons, or with a mass of 
these cocoons fastened to 
some object near them 
(Fig. 30, Page 136). These 
caterpillars have been 
killed by the larvae of 
some Braconid which 
have gnawed their way 
out of the worm and spun 
cocoons in which to com- 
plete their own develop- 
ment. 

One of the most inter- 
esting forms of this family 
belongs to the genus Aph- 
idus. These minute para- 
sites live within the bod- 
ies of aphids. When ma- 
ture the parasite escapes 
through a hole which it 



Btag mA p inmn t j JiH i iHnmU 




Fig. 30. A Cabbage-worm killed by the Larvae 
of a Braconid, the Cocoons of which are fastened 
to the Window-screen near it (Enlarged) 



136 



Beneficial Insects 

gnaws in its dead host. If a colony of aphids is examined, especially in 
the latter part of the season, many brown and much inflated individuals 
will be observed. These are dead, and if no hole is to be seen on their 
backs they harbor one of these little parasites. Whole colonies of plant 
lice are often wiped out by these little insects. 

Figure 6, Plate I, Page 11 represents a Braconid which is parasitic 
upon cutworms. Figure 7, Plate II, Page 11 represents a cocoon of this 
same species. 

Figure 14, Plate V, Page 19 represents another Braconid which was 
reared from a sugar beet webworm cocoon. 

3. CHALCIS -FLIES 

(Fig. 8, Plate I, Page 1 1 ; Fig. 4, Plate IX, Page 27) 

The Chalcis-flies are among the smallest parasitic Hymenoptera. 
Some species are not over one-hundreth of an inch long. They are 
usually black with strong metallic reflections. Some appear quite green, 
while others are yellow. These flies can be recognized by the lack of 
veins in the wings (Fig. 8, Plate I, Page 11). This Chalcis-fly, as already 
stated, is parasitic upon cutworms. (See page 44, and Figure 4, Plate 
IX, Page 27). 

The greater part of the parasites of small insects belong to this 
family. Some are parasitic upon scale insects. One species is the most 
effective natural check on the cabbage-worm. 

Some Chalcis-flies are parasitic within the eggs of other insects. 



137 





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146 



BIBLIOGRAPHY 

The following is a bibliography of the references quoted in this Bulletin and a few 
other publications on related subjects : 

A. References Quoted: 

E. H. Streckland, "Control of Cutworms in the Prairie Provinces,'' Circular No. 6, 
Department of Agriculture, Dominion of Canada (1916). 

Prof. R. A. Cooley, "Observations on the Life History of the Army Cutworm, 
Chorizagrotis auxiliaris," Journal of Agricultural Research, Volume VI, No. 23 (1916). 

G. E. Bensel, "Control of the Variegated Cutworm in Ventura County, California," 
Journal of Economic Entomology, Vol. IX, No. 2 (1916). 

J. J. Davis, "Common White Grubs," Farmers' Bulletin No. 543, U. S. Depart- 
ment of Agriculture (1913). 

John E. Graf, "A Preliminary Report on the Sugar-beet Wireworm," Bulletin No. 
123, Bureau of Entomology, U. S. Department of Agriculture (1914). 

J. R. Parker, "Life History of the Sugar-beet Root-louse, Pemphigus betae," Journal 
of Economic Entomology, Vol. VII, No. 1 (1914). 

J. R. Parker, "Sugar Beet Root Louse Controlled by Irrigation — Four Years 
Summary." 

J. R. Parker, "Life History and Habits of Chloropisca glabra Meign.," Journal of 
Economic Entomology, Vol. XI, No. 4 (1918). 

Harry B. Shaw, "Control of the Sugar-beet Nematode," Farmers' Bulletin No. 772, 
U. S. Department of Agriculture (1916). 

C. S. Scofield, "The Nematode Gallworm on Potatoes and Other Crop Plants in 
Nevada," Circular No. 91, Bureau of Plant Industry, U. S. Department of Agricul- 
ture (1912). 

Davis and Satterthwait, "Life-history Studies of Cirphis unipuncta, the True Army 
Worm," Journal of Agricultural Research, Vol. VI, No. 21 (1916). 

J. A. Hyslop, "The Alfalfa Looper," Bulletin No. 95, Part VII, Bureau of Ento- 
mology, U. S. Department of Agriculture (1912). 

Mr. Koebels, Bureau of Entomology Notes, No. 95-K. 

H. O. Marsh, "Biologic and Economic Notes on the Yellow-bear Caterpillar," 
Bulletin No. 82, Part V, Bureau of Entomology, U. S. Department of Agriculture (1910). 

Dr. F. H. Chittenden, "A Brief Account of the Principal Insect Enemies of the 
Sugar Beet," Bulletin No. 43, Division of Entomologv, U. S. Department of Agricul- 
ture (1903). 

Prof. R. A. Cooley, "Spinach Carrion Beetle," Journal of Economic Entomology, 
Vol. X, No. 1 (1917). 

E. O. G. Kelly, "A New Sarcophagid Parasite of Grasshoppers," Journal of Agri- 
cultural Research, Vol. II, No. 6 (1914). 

F. B. Milliken, "The False Chinch Bug and Measures for Controlling It," Farmers' 
Bulletin No. 762, U. S. Department of Agriculture (1916). 

Boniquit and Slake, "Wild Vegetation as a Source of Curly-top Infections of Sugar 
Beets," Journal of Economic Entomology, Vol. X, No. 4 (1917). 

J. H. and A. B. Comstock, "Manual for the Study of Insects" (1909). 

V. L. Wildermuth, "California Green Lacewing Fly," Journal of Agricultural 
Research, Vol. VI, No. 14 (1916). 

B. Other Publications on Related Subjects: 

H. T. French, "The Beet Army Worm," Information Circular of the Colorado 
Agricultural College. 

E. D. Ball, "The Beet Leafhopper and the Curly-Leaf Disease That It Transmits," 
Bulletin No. 155, Utah Agricultural College Experiment Station (1917). 

Herbert H. Bunzel, "A Biochemical Study of the Curly-top of Sugar Beets," Bulle- 
tin No. 277, Bureau of Plant Industry, U. S. Department of Agriculture (1913). 

147 



E. O. G. Kelly and T. S. Wilson, "Controlling the Garden Webworm in Alfalfa 
Fields," Farmers' Bulletin No. 944, U. S. Department of Agriculture (1918). 

Ernst A. Bessey and L. P. Byars, "The Control of Root-knot," Farmers' Bulletin 
No. 648, U. S. Department of Agriculture (1915). 

C. O. Townsend, "Curly-top, A Disease of the Sugar Beet," Bulletin No. 122, 
Bureau of Plant Industry, U. S. Department of Agriculture (1908). 

Harry B. Shaw, "The Curly-top of Beets," Bulletin No. 181, Bureau of Plant Indus- 
try, U. S. Department of Agriculture (1910). 

C. O. Townsend, "Field Studies of the Crown-gall of Sugar Beets," Bulletin No. 203, 
U. S. Department of Agriculture (1915). 

F. B. Milliken, "Grasshoppers and Their Control on Sugar Beets and Truck Crops," 
Farmers' Bulletin No. 691, U. S. Department of Agriculture (1915). 

Charles R. Jones, "Grasshopper Control," Bulletin No. 233, The Agricultural 
Experiment Station of the Colorado Agricultural College (1917). 

W. R. Walton, "Grasshopper Control in Relation to Cereal and Forage Crops," 
Farmers' Bulletin No. 747, U. S. Department of Agriculture (1916). 

E. D. Ball, "How to Control the Grasshoppers," Bulletin No. 138, Utah Agricultural 
College Experiment Station (1915). 

Leland O. Howard, "Insect Book" of the "New Nature Library" (1914). 

F. H. Chittenden, "Insects Injurious to Vegetables" (1907). 

E. D. Sanderson, "Insect Pests of Farm, Garden and Orchard." 

J. R. Parker, "Influence of Soil Moisture upon the Rate of Increase in Sugar-beet 
Root-louse Colonies," Journal of Agricultural Research, Vol. IV, No. 3 (1915). 

C. P. Gillette and Geo. M. List, "Insects and Insecticides," Bulletin No. 210 of the 
Agricultural Experiment Station of the Colorado Agricultural College (1915). 

Singerland and Crosby, "Manual of Fruit Insects." 

E. W. Scott, W. S. Abbott and J. E. Dudley, Jr., "Results of Experiments with 
Miscellaneous Substances Against Bedbugs, Cockroaches, Clothes Moths, and Carpet 
Beetles," Bulletin No. 707, U. S. Department of Agriculture (1918). 

Harry B. Shaw, "The Sugar Beet Nematode and Its Control," Reprint from 
"Sugar." 

Wm. H. White, "The Sugar-beet Thrips," Bulletin No. 421, U. S. Department of 
Agriculture (1916). 

H. O. Marsh, "The Sugar-beet Webworm," Bulletin No. 109, Part VI, Bureau of 
Entomology, U. S. Department of Agriculture (1912). 

H. R. Cox, "Weeds: How to Control Them," Farmers' Bulletin No. 660, U. S. 
Department of Agriculture (1915). 



-<48 



INDEX 



A 

Abdomen of Insects. . .29, 30, 43, 46, 104 

Acid, Arsenous 33 

Adult Insects 29, 30 

Agents, County 2, 4 

Agricultural College 2, 4 

Air-slaked Lime 32, 89 

Alaus oculatus 52 

Alfalfa, 5, 6, 8, 39, 40, 41, 45, 47, 
50, 51, 53, 63, 66, 71, 72, 75, 
7b, 81, 82, 84, 85, 86, 94, 98, 

101, 104, 127 

Alfalfa Cutworm 41 

Alfalfa Looper 8, 20, 81-84, 136 

Nature of Injury 82 

Methods of Control 82 

Description 82, 83 

Egg 82, 83 

Caterpillar 83 

Cocoon 83. 

Pupa 83 

Moth 83 

Life History 83 

Natural Enemies 83, 84 

Alfalfa Webworm 7, 20, 84, 85 

Nature of Injury 84 

Methods of Control 84 

Description 84, 85 

Worm 84, 85 

Pupa 85 

Moth 85 

Life History 85 

Natural Enemies 85 

Alkali 89, 90 

Alkali-beetle or 

Alkali-bug. ... 7, 8, 22, 29, 89, 90, 92, 133 

Allseed 63 

Amara, Egg-eating 106 

Amara obesa 1 06 

Amaranthus 86 

Ambrosia 86 

Ambush-bug 133 

Annual Meadow-grass 63 

Antennae of Insects 29 

Ants 114 

Aphids or Plant Lice, 3,1 11-1 16,123, 134, 137 

Nature of Injury 114 

Methods of Control 114, 115 

Description 115 

Life History 115 

Natural Enemies 115, 116 

(See also Plant-lice) 

Aphidus, Genus 136 

Aphis-lion 26, 116, 133, 134 

Appendix , 2, 3, 138-146 

Archytus apicifere 81 

Arsenate of Lead, 32, 73, 79, 82, 86, 88, 96 



Arsenical Poisons 33, 86 

Arsenous Acid 33 

Artificial Methods of Insect Control 31,32 

Ash, White 112 

Ash-gray Blister-beetle 22, 98 

Asparagus 63, 65, 66, 86 

Assassin-bug 133 

Authocoris melanocerus 59 

B 

Bacteria ■ 61 

Bacterial Diseases 83, 109 

Bait, Poisoned, 32, 39, 40, 47, 53, 

79, 94, 95 

Banded Flea-beetle 16, 92, 93 

Description 92 

Egg 92 

Larva 92 

Adult 92 

Life History 93 

Barley 63, 65, 66 

Beak, of Sucking Insects 29 

Beans 53, 119 

Dwarf Pea 63 

Lima 63, 66, 86 

Soy •. 63, 66 

String 86 

"Bearded Roots" 61 

Bedbugs 133 

Bees 29, 30, 78 

Beet or Spinach Leaf-miner. .. 14, 1 10, 1 1 1 

Nature of Injury 110 

Methods of Control 110, 111 

Description Ill 

Egg Ill 

Miner Ill 

Pupa Ill 

Adult HI 

Life History Ill 

"Beet Weariness" 59 

Beetles, 1, 3, 29, 30, 48, 50, 51, 67, 

78, 88, 105 
See also : 

Black Carrion-beetle 

Blister-beetle 

Bombardier-beetle 

Click-beetle 

Colorado Potato-beetle 

Egg-eating Amara 

Fiery Hunter 

Flea-beetles 

Banded Flea-beetle 
Potato Flea-beetle ' 
Three-spotted Flea-beetle 
Ground Beetles 
Lady-beetle or Lady-bug 
Larger Sugar Beet Leaf-beetle 
or Alkali-beetle 



149 



INDEX— Continued 



Beet'es — Continued 
Leaf Beetles 
Leaf-eating Beetles 
Sacred Beetle of Egypt 
Snapping-beetle 
Tiger-beetle 

Western Beet Leaf -beetle 
Beets, Garden. . . .63, 66, 86, 88, 99, 110 

Beets, Stock 86 

Beets, Sugar 

(See Sugar Beets) 

Beet-seed Louse, Black 14, 1 17-1 19 

Beneficial Insects 3, 26, 129-137 

Parasitic 3, 43, 52, 135-137 

Predacious 3, 43, 52, 130-135 

Bibliography 2, 3, 147, 148 

Birds, 43,45, 46, 51, 54, 57, 81,85, 

87, 88, 108 

Biting Insects 1, 29, 31, 32 

Mouth Parts of 29 

Control of 32 

Biting Leaf Feeders 3, 67 

Biting Root Feeders 3,38 

Black Beet-seed Louse 14, 1 17-1 19 

Nature of Injury 117 

Methods of Control 117 

Description 118 

Wingless Lice 118 

Pupae 118 

Winged Lice 118 

Life History 118, 119 

Blackberry 86 

Blackbird 45, 81, 108 

Blackbird, Crow 51 

Black Blister-beetle 22, 98 

Black Carrion-beetle 94 

Black Leaf 40 33, 114, 117 

Blight 124 

Blight, Western 124 

Blister-beetle 22", 96-98, 106 

Nature of Injury 96 

Methods of Control 96 

Description 97, 98 

Egg 97 

First Larval Stage 97 

Second Larval Stage 97 

Third Larval Stage 98 

Pupa 98 

Adult 98 

Life History 97,98 

Blister-beetle, Ash-gray 22, 98 

Blister-beetle, Black 22, 98 

Bombardier-beetle 130 

Bordeaux Mixture 92 

Botrytis bassiana 87 

Braconids, 3, 10, 18, 43, 77, 135, 136, 137 

Breathing of Insects 29 

Brown-cyst 64 

Buckwheat 50 

Bugs, True, 3, 12, 29, 30, 111, 119, 

122, 132, 133 

Burning 32, 63, 89, 120, 125, 127 

Burning Bush 118 



Burrowing Owl 108 

Butcher-bird 54 

Butterflies 29, 30, 67 

C 

Cabbage 63, 65, 66, 86, 88 

Cabbage-worm 136, 137 

California Devastating Locust 100 

California Shrike 54 

Carina 86 

Cantaloupe 63, 86 

Care of Sprayers 34, 35 

Carrion-beetle, Black 94 

Carrion-beetle, Spinach 7, 22, 94, 95 

Carrots 66, 86 

Catalpa 66 

Caterpillar Killer 130 

Caterpillars, 1, 3, 29, 30, 38, 67, 71, 

81, 130, 135, 136 

Caterpillars, Leaf-eating 67 

Caterpillar, Yellow-bear 8, 18, 86, 87 

Caterpillar, Zebra 8, 14, 87, 88 

Cauliflower 63, 66, 86 

Celery 63, 66, 86 

Chalcis-fly 3, 10, 26, 43, 44, 135, 137 

Chloropisca glabra 59 

Chenopodium 86 

Cherry 66, 86 

Chiggers 106 

Chinch Bug 119 

Chinch Bug, False, 6, 24, 29, 119-121, 123 

Chitin 30 

Chrysalis 30 

Classification of Insects 3,31 

Clean Culture, 1, 32, 91, 94, 104, 

111, 120, 122, 125, 127 

Click-beetle 52, 53, 54 

Clover 40, 50, 66 

Crimson 63 

" Sweet 8,63,66,82 

" White 63 

Clover Leaf-hopper 24, 126-128 

Nature of Injury 127 

Methods of Control 1 27 

Description 127 

Egg 127 

Nymph 127 

Adult 127 

Life History 127, 128 

Cocoon 44, 45, 76, 83, 85, 87, 136 

Colorado Potato-beetle 89, 132 

College, Agricultural 2, 4 

Colored Plates 1, 2, 3, 4, 1 1-27 

Common Mallow 125 

Compound Eye (of Insect) 76 

Contact Poisons 32,33, 114 

Control of Insects 31-33 

Natural Methods 31,32 

Cultural Methods 31,32 

Artificial Methods 31, 32, 33 

Control of Biting Insects 32, 33 

Control of Sucking Insects 33 

Cooper's Hawk 109 

Corn 50, 53, 63, 65, 66, 86, 99 



150 



INDEX— Continued 



Corn Root-louse 38 

Corn Root-worm 31,38 

Cost of Spraying 47, 74 

Cottonwood 56, 58 

Cottonwood, Narrow-leaf 57, 58, 113 

County Agents 2, 4 

Cow Pea 63, 66 

Cress 63 

Crickets, Field... ...... 3, 16, 67, 109, 110 

Crimson Clover 63 

Crop Rotation, 1,31, 50, 53, 57, 62, 63, 65 

Crow 5 1 , 54 

Crow Blackbird 51 

Cucumbers 63, 66, 93 

Cultural Methods of Insect Control 3 1 

Curly-top 8, 24, 60, 61, 124, 125 

Currants 86 

Cutworms, 3, 4, 5, 20, 26, 38-48, 87, 

130, 137 

Nature of Injury 38, 39 

Where to Look for the Worms ... 39 

Methods of Control 39, 47 

Cutworm, Alfalfa 41 

Cutworm, Pale Western, 10, 41, 45, 46, 47 

Cutworm, Variegated 8, 22, 47, 48 

Cutworm, Western Army, 8, 10, 

41-45, 46, 47, 88, 136 
D 

Dahlia 86 

Dandelion 63 

Destruction of Summer Hosts 117 

Destruction of Weeds 71, 72 

Development of Insects 3, 29, 30 

Differential Hopper 16, 100 

Digger-wasp 20, 43, 44, 45, 134, 136 

Digger-wasp enemy of Cutworms. . 44, 45 

Disc 50, 53 

Discing 31, 40, 50, 53, 103, 104 

Diseases of Insects. ... 59, 83, 88, 109, 121 

Dock (Rumex) 86 

Duck Hawk 109 

Dwarf Pea Bean 63 

E 

Eelworms 38, 59, 64 

Egg-eating Amara 106 

Egg Plant 66, 86 

Eggs, Grasshopper 96, 97, 104, 105 

Eggs of Insects 30, 3 1 

Elis sexcincta 52 

Elm 66 

Empusa aphidis 59 

Empusa grylli 1 09 

Emulsion, Kerosene 33, 1 14, 122 

Euonymus Sp 118 

Eutettix strobi 24, 128 

See note opposite Clover Leaf- 
Hopper in Appendix 
Eyes of Insects 76 

F 

Fall Plowing 3 1 . 40, 50, 53 

False Chinch Bug. . .6, 24, 29, 1 19-121, 123 

Nature of Injury 119 

Methods of Control 120, 121 



Description 

Egg 

Nymph 

Adult 

Life History 

Natural Enemies . 

Fanweed 

Feelers of Insects. . . 



121 

121 

121 

121 

121 

121 

6 

29 

Field Crickets 3, 16, 67, 109, 1 10 

Fieldmen 2, 4 

Fiery Hunter 26, 130 

Flea-beetle 7, 16, 29, 91-93, 96 

Nature of Injury 91 

Methods of Control 91, 92 

Flea-beetle, Banded 16, 92, 93 

Flea-beetle, Potato 16, 93 

Flea-beetle, Three-spotted 16, 93 

Flesh-flies 105 

Flesh-fly parasite of Grasshoppers 16, 105 

Flies 30 

Flies, Chalcis. ..3, 10, 26, 43, 44, 135, 137 

Flies, Flesh 105 

Flies, Ichneumon 3, 10, 20, 43, 83, 135, 136 

Flies, Lace-winged 3, 26, 1 16, 133, 134 

Flies, Parasitic 52, 81 

Flies, Robber 20, 78 

Flies, Syrphus 20, 59, 1 16 

Flies, Tachina 18, 20, 77, 85, 87 

Flies, Two-winged 20, 29, 30, 111, 121 

Flour, Low Grade 32, 89 

Food Plants of Insects 32 

Fossores 44 

Fox Tail, Green 63 

French Bug 89 

Fumigants, Soil ' 65 

Fungi 94 

Fungous Diseases of Insects, 59, 88, 

109, 121, 123 
Furrow Trap 72, 79, 82 



G 



121 



Gaillardia pulchella 

Gallwcrm (See Root-knot Nema- 
tode or Gallworm) 

Garden Beets 63, 1 10 

Garden Peas 63 

Gas Tar 53 

General Discussion of Insects 29-33 

Giant Thorn-headed Worm 50 

Golden-eye (See Lace-winged Fly) 26, 133 

Golden-glow 115 

Goldenrod 98, 133 

Gooseberry 86 

Gordian Worm 107 

Goshawk 109 

Grain, 5, 8, 38, 39, 45, 50, 53, 79, 

80, 94, 101, 119 

Grapes 86 

Grass 49, 54, 80, 99, 123 

Grasshopper Eggs. 16, 26, 96, 97, 104, 105 
Grasshoppers, 1, 3, 8, 16, 18, 29, 30, 

31, 98-109, 130 

Nature of Injury 101 

Methods of Control 101-104 



151 



INDEX— Continued 



Grasshoppers — Continued 

Eggs 16, 96, 97, 104, 105 

Life History 104, 105 

Natural Enemies 105-109 

Diseases of 109 

Great Horned Owl 108, 109 

Green-berried Nightshade 94 

Green Fox Tail 63 

Green Peach-aphis 24, 116, 117, 118 

Nature of Injury 116 

Methods of Control 116 

Description 116 

Stem-mother 116 

Winged Lice 116, 117 

Wingless Lice 116, 117 

Females 117 

Males 117 

Eggs 117 

Life History 116, 117 

Ground Beetles, 26, 43, 54, 81, 105, 

108, 130 
See: Bombardier-beetle 
Egg-eating Amara 
Fiery Hunter 

Ground Squirrel 108 

Grubs 30, 31, 38, 43, 45, 48, 50, 97 

Grubs, White, 3,5, 10,31,38,48-52, 

53, 54,97, 134 
Gyrfalcon 109 

H 

Hair Snake 107 

Hair Worm 16, 107, 108 

Hand Picking 117, 120, 122 

Hand Sprayer 36 

Harrow 50, 53 

Harrowing 31, 103, 104 

Harvestmen 106 

Hawk 108, 109 

Hawk, Sharp-shinned 109 

Hawk, Sparrow 109 

Hawk, Swainson's 109 

Head of Insects 29 

Heart of Insects . 46 

Helianthus 86 

Hemiptera 119 

Hemp 63 

Heterodera schachtii 59 

Heteroptera 119 

Hibernation of Insects 32 

Hippodamia convergens 132 

Hogs, Pasturing with 50 

Hollyhock 86 

Home-made Sprayer 37 

Honey Dew 114 

Hopper Dozer 99, 102, 103 

Hops 63 

Horseradish 65, 66 

Horse Bean 119 

"Hunger Roots" 61 

Hyacinth 86 

Hymenoptera < 137 



I 

Ichneumon-fly 3, 43, 83, 135, 136 

Ichneumon-fly parasite of Alfalfa 

Looper 20, 83, 136 

Ichneumon-fly parasite of Western 

Army Cutworm 10, 43, 136 

Identification of Insects 1,2 

Index 2, 3, 149-157 

Insects 1, 3, 29-33 

Abdomen of 29, 30, 43, 46, 104 

Adult 29, 30 

Antennae of 29 

Beneficial Insects 3, 26, 129-137 

Parasitic 3, 43, 52, 135-137 

Predacious 3, 43, 52, 130-135 

Biting 1, 3, 29, 31, 32 

Biting Leaf Feeders 3, 67 

Biting Root Feeders 3, 38 

Breathing of 29 

Classification of 3,31 

Control of 31-33 

Control of Biting Insects 32, 33 

Control of Sucking Insects 33 

Development of 3 , 29, 30 

Diseases of 59, 83, 88, 109, 121 

Eggs of 30,31 

Eyes of 76 

Feelers of 29 

Food Plants of 32 

General Discussion of 29-33 

Head of 29 

Heart of 46 

Hibernation of 32 

Identification of 1,2 

Integument of 30 

Jaws of 29, 3 1 

Larvae of 29, 30 

Leaf-eating 79 

Leaf Feeders 3, 31, 67, 111 

Biting 3, 67 

Sucking 3 , 111 

Legs of 29 

Metamorphosis of 29, 30 

Methods of Control of 3,3 1-33 

Artificial 31, 32, 33 

Cultural 31, 32 

Natural 31 

Molting of 30 

Mouth Parts of 29, 30, 3 1 

Natural Enemies of, 31, 43, 44, 
45, 46, 51, 52, 54, 59, 77, 78, 
81, 83, 84, 85, 87, 88, 105, 106, 
107, 108, 109, 115, 116, 121, 

123, 129-137 

Parasitic Insects (Beneficial), 3, 

43, 52, 135-137 

Predacious Insects (Beneficial), 3, 

43, 52, 130-135 

Proboscis of 29, 76 

Prolegs of. ... : 29 

"Props" of ."... 29 

Pupa of 30 



152 



INDEX— Continued 



Insects — Continued 

Root Feeders 3, 31, 38, 67 

Biting 3, 38 

Sucking 3, 55 

Scales of 134, 137 

Skin of 30 

Spiracles of 29 

Structure of 3, 29 

Sucking Insects. . . .3, 29, 31, 32, 33, 119 

Sucking Leaf Feeders 3, 111 

Sucking Root Feeders 3, 55 

Thorax of 29 

Tracheae of 29 

Wings of 29 

Insecticides 32 

Insect Powders - 33 

Integument of Insects 30 

Introduction to Bulletin 1-8 

Irrigation 1 , 56, 62, 72, 84, 92 

Early 56 

Fall 56, 57 

Spring 56, 57 

J 

Jaws of Insects 29, 3 1 

June-bug 48, 50 

K 

Kafir 65, 66 

Kale 63, 65, 66 

Kansas Mixture, 39, 40, 94, 101, 102, 103 

Formula for 39, 101 

How to Make 39, 40, 101 

How to Apply 40, 102 

Time to Apply 40, 101, 102 

Treating Fields Before Planting 40 

Where to Apply 102 

Kerosene 96, 103, 1 14, 120 

Kerosene Emulsion 33, 114, 122 

Key for Determining Insect Injury 

to Sugar Beets 1, 2, 3, 4, 5-8 

Explanation of 4 

Knapsack Sprayer 36, 89 

Kohl-rabi 63 

L 

Lace-winged Fly 3,26, 116, 133, 134 

Lady-beetle 22, 26, 59, 115, 132 

Lady-beetle enemy of Sugar Beet 

Root-lice 12, 59 

Lady-bug 132 

Lamb's-quarters, 



128 
47 

133 



69, 71, 75, 86,93, 
94, 111 

Lantern Trap 

Larger Sugar Beet Leaf-beetle, or 
Alkali-beetle. ... 7, 8, 22, 89, 90, 92 

Nature of Injury 89 

Methods of Control 89, 90 

Description 90 

Egg 90 

Larva 90 

Pupa ' 90 

Beetle 90 

Larvae of Insects 29, 30 

Late Planting 32, 41 



Laundry Soap : . . . 

Lead, Arsenate of, 32, 73, 79, 82, 86, 88 

Leaf-beetle, Western Beet 22, 90, 

Leaf Beetles 88, 89, 

Leaf-eating Beetles 88, 89, 

Leaf-eating Caterpillars 

Leaf-eating Insects 67, 

Leaf Feeders 3, 31, b7, 

Biting 3, 

Sucking 3, 

Leaf-hopper, Clover 24, 126- 

Leaf-hopper, Rose 

Leaf-hopper, Sugar Beet. . .8, 24, 123- 

Leaf-hoppers 7, 111, 123- 

Leaf-miner, Beet or Spinach. . 14, 1 10, 

Leaf-miners 1, 3, 67, 110, 

Legs of Insects 

Lentils 

Lesser Migratory Locust 

Lettuce 63 , 

Lima Beans 63, 66, 

Lime 33, 63, 

Lime, Air Slaked 32, 

Lime, Quick 33, 

Lime -sulphur Mixture. . .32, 115, 116, 

Live Hopper Machine 

Live Stock 40, 55, 62, 74, 

Poisoning of 40, 

Locust, California Devastating. . . . 

Locust, Lesser Migratory 

Locust Mite 18, 106, 

Locust, Red-legged 16, 

Locust, Rocky Mountain, 98, 100, 

101, 106, 

Love-grass 

Low Grade Flour 32, 

Loxostege similaris 

Lupine, Yellow 



114 

,96 

91 

91 

96 

67 

79 

111 

67 

111 

128 

123 

126 

128 

111 

111 

29 

63 

100 

66 

86 

89 

89 

63 

117 

103 

102 

74 

100 

100 

107 

100 

107 

121 

89 

84 

63 



M 

Macrosiphum 115 

Maggots 30, 77 

Mallow, Common 125 

Mangels 110 

Manuring 1 

Masked Bedbug Hunter 133 

May-beetle 48, 5 1 

Meadow 5, 49, 51, 52, 53, 54 

Meadow-grass, Annual 63 

Meadow Lark 45, 81 

Meadow Oat-grass, Tall 63 

Mealy-bug 134 

Mechanical Methods of Insect 

Control 96 

Metamorphosis of Insects 29, 30 

Methods of Control of Insects ... .3, 31-33 

Artificial 31, 32, 33 

Cultural 31, 32 

Natural • 31 

Mice 108 

Microgaster Sp 10 

Millers 38, 67 

Millet 63 

Milo 65, 66 

Miners, Leaf (See Leaf-miners) 



153 



INDEX— Continued 



Miscible Oils 32 

Mite, Locust 18, 106, 107 

Mites 29, 106, 134 

Mollugo verticillata 121 

Melting of Insects 30 

Morning-glory 86 

Moths 29, 30, 67, 78 

Moths, Owlet 38 

Mouth Parts of Insects 29, 30, 31 

Mowing 82, 84 

Mud-dauber 135 

Muskmelon 66 

Mustard 63 

N 

Narrow-leaf Cottonwood 57, 58, 113 

Natural Enemies of Insects, 31, 43, 
44, 45, 46, 51, 52, 54, 59, 77, 
78, 81, 83, 84, 85, 87, 88, 105, 
106, 107, 108, 109, 115, 116, 

121, 123, 129-137 
Natural Methods of Insect Control 31, 32 
See: Burning. .32, 63, 89, 120, 125, 127 
Clean Culture, 32, 91, 94, 

104, 111, 120, 122, 125, 127 
Crop Rotation, 31, 50. 53, 

57, 62, b3, 65 
Destruction of Summer 

Hosts 117 

Destruction of Weeds 71, 72 

Discing.. 31, 40, 50, 53, 103, 104 

Hand Picking 117, 120, 122 

Harrowing.. . .31, 50, 53, 103, 104 

Irrigation 56, 62, 72, 84, 92 

Late Planting 32, 41 

Mechanical Measures 96 

Mowing 82, 84 

Picking Infested Leaves . . 110 
Plowing, 31, 32, 40, 50, 53, 

56, 57, 104 

Rolling 40 

Scattering 91 

Sticky Shields 120 

Nematode 6, 59-66 

Root-knot Nematode or Gall- 
worm 3,6, 64-66 

Sugar Beet Nematode. .3, 6, 14, 

31, 38, 59-64, 65 

Nicotine Sulphate 121 

Nightshade, Green-berried 94 

Nymphs 30 

O 

Oats 63, 65, 66, 101 

Oils, Miscible 32 

Oils, Soluble 33 

Onions 66 

Outline of the Bulletin 1 , 2, 3 

Ovipositor 43, 129, 136 

Owl, Great Horned 108, 109 

Owlet Moths 38 

Owls = 108, 109 

P 

Pale Western Cutworm. . 10, 41, 45, 46, 47 
Description 45, 46 



Worm 45, 46 

Pupa 46 

Moth 46 

Life History 46 

Natural Enemies " " 46 

Parasites 43, 44, 129, 130, 135 

Parasitic Flies 52, 81 

Parasitic Insects 3, 43, 52, 135-137 

Paris Green, 32, 34. 35, 39, 40, 47, 
53, 68, 70, 72, 73, 74, 79, 82, 

86, 88, 89, 92, 96, 101 

Paris Green Applied Dry 32, 89 

Paris Green, Caution Regarding. . . 37 

Parsnips 63, 86 

Pasture 5, 49, 52, 53, 54, 80 

Pasturing with Hogs 50 

Pea Bean, Dwarf 63 

Peach 66, 116 

Peach-aphis, Green 24, 116, 117, 118 

Peanuts 86 

Peas 50, 63, 66, 86, 99 

Cow 63 , 66 

Garden 63 

Sweet 63 

Pennycress 121 

Peppergrass 119, 121 

Pheasants 5 

Picking Infested Leaves 110 

Pictured Soldier-bug 133 

Pigweed Ill 

Pigweed, White Ill 

Pimply Potatoes 93 

Pinks 63 

Plant-bug. Tarnished 6, 122, 123 

Plant-lice, 3, 7, 29, 30, 111-116, 132,134, 137 

Nature of Injury 114 

Methods of Control 114, 115 

Description 115 

Life History 115 

Natural Enemies 115, 116 

Planting, Late 32, 41 

Plowing, 1, 31, 32, 40, 50, 53, 56, 57, 104 

Plowing, Fall 31, 40, 50, 53 

Plum 116 

Poison 72, 79, 82, 84, 86, 92, 96, 1 14 

Poisoned Bait, 32, 39, 40. 47, 53, 79, 94, 95 

Poisoning Stock 40, 74 

Poisons, Arsenical 33, 86 

Poisons, Contact 32, 33, 114 

Poisons, Stomach 32, 114 

Poppy 118 

Potato-beetle 89, 133 

Potato-beetle, Colorado 89, 132 

Potato Flea-beetle 16, 93 

Description 93 

Larva 93 

Adult 93 

Life History 93 

Potatoes, 45, 50, 53, 63, 65, 66, 86, 

93, 96, 133 

Potatoes, Pimply 93 

Poultry 40, 85, 102, 104 

Poverty-weed 91 , 92 

Predacious Insects 3, 43, 52, 130, 135 



154 



I NDEX— Continued 



S 



Proboscis of Insects ' 29, 76 

Prolegs of Insects 29 

"Props" of Insects 29 

Psyllids 134 

Pumpkin 66, 86, 94 

Pupa of Insects 30 

Puparium 30 

Pyrgota undata 52 

Q 

Quick Lime 33, 63 

R 

Rabbit Brush 46 

Radish 63, 66, 86, 121 

Rape 63, 66 

Raspberry 86, 119 

Red-headed Woodpecker 108 

Red-legged Locust 16, 100 

Red Top 65, 66 

Reference Figures, Explanation of 2 

Repellents 33 

Rhubarb 86, 87 

Robber-fly 20, 78 

Robin 45 

Rocky Mountain Locust, 98-100, 

101, 106, 107 

Rolling 40 

Root Feeders 3, 3 1 , 38, 67 

Biting Root Feeders 3, 38 

Sucking Root Feeders 3, 55 

Root-knot Nematode or Gallworm 

3, 6, 64-66 

Nature of Injury 64 

Methods of Control 65 

Life History 65, 66 

Root-louse 38, 55 

See: Corn Root -louse 

Sugar Beet Root-louse 

Root-worm, Corn 31,38 

Rose Leaf-hopper 123 

Roses 123 

Rotation 1, 31, 50, 53, 57, 62,63, 65 

Rumex (Dock) 86 

Russian Thistle, 69, 71, 75, 86, 90, 93, 98 

Rutabaga 63 

Rye , 63, 65, 66 



Sacred Beetle of Egypt 48, 49 

Salsify 66 

Saltbush 90 

Scale Insects 134, 137 

Scattering Insects 91 

Scoliidae 134 

Scorpions 1 06 

Seed Treatment 53 

Sharp-shinned Hawk 109 

Sheep, Pasturing with 62, 63 

Shepherd 's-purse 6, 119, 120, 121 

"Shot Holes" 91 

Shrike, California 54 

Shrubs 88, 115, 118 

Skin of Insects 30 

Skip-jack 52 

Skunk 51, 54 



Skunk, Spotted 54 

Snapping-beetle 52 

Soap 33, 114, 121 

Soap, Whale Oil 33, 114, 120, 121 

Soap, Laundry 114 

Sod 5 

Soil Fumigants 65 

Solarium rostralum 86 

Soldier-bug, Pictured 133* 

Solitary Wasp 20, 77, 78, 135 

Solitary Wasp enemy of Sugar Beet 

Webworm 77, 78, 135 

Soluble Oils 33 

Sorghum 63, 65, 66 

Soy Beans 63, 66 

Spanish-fly 96 

Spanish Needle 86 

Sparrow Hawk 109 

Spiders 29, 106, 135 

Spider-wasp 134 

Spinach 63, 66, 94 

Spinach Carrion-beetle 7, 22, 94, 95 

Nature of Injury ! 94 

Method of Control 94, 95 

Description 95 

Egg 95 

Larva 95 

Pupa 95 

Adult 95 

Life History 95 

Spinach Leaf-miner 110, 111 

(See Beet or Spinach Leaf-miner) 

Spindle Tree 118 

Spiracles of Insects 29 

Spotted Skunk 54 

Sprayers 33-37 

Care of Sprayer 34, 35 

Hand Sprayer 36 

Home-made Sprayer 37 

Knapsack Sprayer 36, 89 

Testing of Sprayer 35 

Traction Sprayer 33, 34, 47, 73 

Spraying, 32, 35, 47, 73, 74, 79, 89, 

91, 116, 117, 120 

Spraying, Cost of 47, 74 

Spraying, Winter 117 

Squash 66, 86, 94 

Squirrel, Ground 108 

Stack Bottoms 80 

Stacking Grounds 80 

Sticky Shields 120 

Stink-bug '....119, 133 

Stink-bug enemy of Potato-beetle 133 

Stink-grass 121 

Stomach Poisons 32, 1 14 

Strawberry 50, 65, 66 

Strawberry Bush 118 

String Beans 86 

Structure of Insects 3, 29 

Sucking Insects 29, 31, 32, 33, 119 

Control of 33 

Mouth Parts of 29, 3 1 

Sucking Leaf Feeders 3, 111 

Sucking Root Feeders 3,55 



155 



INDEX— Continued 



Sugar Beets, 1, 2, 3, 4, 5, 7, 45, 50, 
53, 55, 57, 63, 75, 82, 85, 86, 
94,96, 101, 110, 119, 122, 123, 

125, 127, 128 
Sugar Beet Leaf-hopper. ... 8, 24, 123-126 

Nature of Injury 124, 125 

Methods of Control 125 

Description 126 

Egg 126 

Nymph 126 

Adult 126 

Life History 126 

Sugar Beet Nematode, 3, b, 14, 31, 

38, 59-64, 65 

Nature of Injury 61 

How Spread 61 , 62 

Methods of Control 62, 63 

How to Prevent Spread 62 

How to Check Multiplication . 63 

Description 64 

Egg 64 

Larval Stages 64 

Adult 64 

Brown-cyst Stage 64 

Life History 64 

Sugar Beet Root-louse, 3, 6, 12, 38, 

55-59,111,113 

Nature of Injury 55 

Methods of Control 55, 57 

Description 57, 58 

Egg 57 

Females 57 

Hibernating Lice 58 

Males 57 

Stem-mother 58 

Winged Lice 57, 58 

Winged Migrants 58 

Life History 57, 58 

Natural Enemies 59 

Sugar Beet Webworm, 7, 18, 67-78, 

135, 137 

Nature of Injury 68-71 

Methods of Control 71-73 

Description 74, 75 

Egg 74,75 

Worm 75 

Pupa 75 

Cocoon 75 

Moth 75 

Life History 75-77 

Natural Enemies 77, 78 

Why Growers do not Spray 73, 74 

Sugar Beet Wireworm 53 

Sulphate, Nicotine 121 

Sunflower 63 

Swainson's Hawk 109 

Sweet Clover 8, 63, 66, 82 

Sweet Potatoes 65, 66, 86 

Swine 50 

Syrphus-fly 59, 116 

Syrphus-fly enemy of Sugar Beet 

Root-louse 20, 59 



T 

Tachina-flies 77, 85, 87 

Tachina-fly parasite of Alfalfa 

Webworm 20, 85 

Tachina-fly parasite of Sugar Beet 

Webworm 18, 77 

Tall Meadow Oat-grass 63 

Tarnished Plant-bug 6, 122, 123 

Nature of Injury 122 

Methods of Control 122 

Description 122, 123 

Egg . . ... 122 

Nymph .' .' .' .' .' .' .' .' .' .' .' .' .' .' .' .' .' .' .' 1 22, 1 23 

Adult 123 

Life History 123 

Natural Enemies 123 

Testing of Sprayers 35 

Thorax of Insects 29 

Thread-waisted Wasp 134, 135 

Three-spotted Flea -beetle 16, 93 

Ticks 29, 106 

Tiger-beetle 26, 76, 131, 132 

Tiger-moth, Virginia 87 

Timothy 5, 63, 65, 66 

Tiphia inornata 52, 134 

Tobacco 114 

Tobacco Decoction 115 

Tobacco Preparations 33 

Tomatoes 63, 65, 66 

Tracheae 29 

Traction Sprayer 33, 34, 47, 73 

Trees 115 

True Army Worm 10, 78-81 

Nature of Injury 79 

Methods of Control 79, 80 

Description 80, 81 

Egg 80 

Worm 80 

Pupa 80 

Moth 80, 81 

Life History -. 81 

Natural Enemies 81 

True Bugs, 3, 12, 29, 30, 59, 111, 119, 

122, 132, 133 
A species of True Bug which preys 
upon Sugar Beet Root-lice .... 59 

Tumble-bug 48 

Turkeys 104 

Turnips 63, 86, 88, 99, 101, 121 

Two-lined Hopper 16, 100 

Two-winged Flies 20, 29, 30, 111, 121 

V 

Variegated Cutworm 8, 22, 47, 48 

Nature of Injury 47 

Methods of Control 47 

Description 47, 48 

Egg 47 

Worm 48 

Moth 48 

Life History 48 

Verbesina 86 

Vetch 63, 66 

Virginia Tiger-moth 87 



156 



INDEX— Concluded 



W 

Waahoo (or Wahoo) 118 

Wasps 3, 29, 30, 44, 45, 134, 13? 

Digger-wasp 20, 43, 44, 45, 134, 136 

Solitary Wasp 20, 77, 78, 135 

Spider-wasp 134 

Thread-waisted Wasp 134, 135 

Watermelon 66, 86 

Webworm, Alfalfa (See Alfalfa Web- 
worm) 
Webworm, Sugar Beet (See Sugar 
Beet Webworm) 

Weeds 5, 6, 71, 72, 89, 91 

Western Army Cutworm, 8, 10, 

41-45, 46, 47, 88, 136 

Description 41 , 42 

Worm 41 

Pupa 41 

Moth 41, 42 

Life History 42, 43 

Natural Enemies 43-45 

Western Beet Leaf-beetle 22, 90, 91 

Description 90 

Nature of Injury 90 

Methods of Control 91 

Western Blight 124 

Whale Oil Soap 33, 114, 120 

Wheat 63, 65, 66 

'"Whiskered Beets" 61, 124 

White Ash 112 

White Clover 63 

White Grubs, 3, 5, 10, 31, 38, 48-52, 

53, 54, 97, 134 

Nature of Injury 49, 50 

Methods of Control 50 

Life History 51 

Natural Enemies 51,52 

White Pigweed Ill 

Why Growers do not Spray 73 , 74 

Willow 50 

Winged Lice 57, 58 



Wings of Insects 29 

Winter Spraying 117 

Winthemia Sp 81 

Wireworm 3, 5, 10, 31, 38, 50, 52-54 

Nature of Injury 52, 53 

Methods of Control 53 

Description 53, 54 

Worm 53 

Pupa 54 

Beetle 54 

Life History 54 

Natural Enemies 54 

Woodpecker, Red-headed 108 

Worms 30, 41, 43, 44, 45, 46, 47, 48 



Yellow-bear Caterpillar 8, \l 

Nature of Injury 

Methods of Control 

Description 

Egg 

■ Caterpillar 

Pupa 

Moth ' 

Life History 

Natural Enemies 

Yellow Jacket 

Yellow Lupine 



i, 87 
86 
86 
87 
87 
87 
87 
87 
87 
87 
135 
63 



Zebra Caterpillar 8, 14, 87, 88 

Nature of Injury 88 

Methods of Control 88 

Description 88 

Egg 88 

Caterpillar 88 

Moth 88 

Life History 88 

Natural Enemies 88 



157 



